We analyze the deuteron charge and quadrupole form factors using the latest NN potentials and charge-density operators derived within chiral effective field theory. We derive relations between 1N,2N charge densities and nucleon form factors and employ several recent empirical parametrizations for proton and neutron form factors. We fit low-energy constants appearing in the fifth-order 2N...
I will discuss the origin of the proton mass from the Hamiltonian and gravitational form factor formulations. After examining the mass decomposition in the stress-energy-momentum tensor, it is found that the glue part of the trace anomaly can be identified as the vacuum energy from the glue condensate and gives a CONSTANT restoring pressure which balances that from the traceless part of the...
We establish the existence of a far-from-equilibrium attractor in weakly-coupled gauge theory undergoing one-dimensional Bjorken expansion. We demonstrate that the resulting far-from-equilibrium evolution is insensitive to certain features of the initial condition, including both the initial momentum-space anisotropy and initial occupancy. We find that this insensitivity extends beyond the...
The large collaborations in high-energy physics analyze a large amount of data on a daily basis. Different practices have been consolidated and improved through the past decade. A brief overview of the most common statistical techniques used in searches for new physics and precision measurements is presented.
It is well known that a static quark-antiquark pair has a spectrum of flux-tube excitations in a pure gauge theory. In this talk I will show numerically that, in a variety of gauge Higgs theories in the non-confining Higgs phase, there is also a spectrum of excitations of the gauge and Higgs fields surrounding a static fermion-antifermion pair. These are localized and stable excitations which...
The mixing parameter $\Delta \Gamma_{12}^s$ is an important flavor observable that governs the lifetime difference $\Delta \Gamma_s$ of the neutral $B_s$ mesons. The state-of-the-art Standard Model prediction for $\Delta \Gamma_s$ is compatible with the HFLAV world average, yet the theoretical uncertainties due to uncalculated perturbative corrections are still large. In this talk I will...
The connection between QCD and string theory is expected through the gauge/gravity correspondence. Particularly, it predicts that the baryons are discribed by D-branes. (This relation is analogous to the Skyrmion model where the baryons are obtained as solitons, since D-branes are also solitons in string theory.) In this talk, I will review how the D-branes behave as baryons, and discuss our...
LA-UR-21-25112 - Neutron stars contain the largest reservoirs of degenerate fermions, reaching the highest densities we can observe in the cosmos, and probe matter under conditions that cannot be recreated in terrestrial experiments. Throughout the Universe, a large number of high-energy, cataclysmic astrophysical collisions of neutron stars are continuously occurring. These collisions provide...
In the past years, the light-front holographic Schrodinger Equation, of Brodsky and de Teramond, has played a role in hadronic physics analogous to that of the ordinary Schrodinger Equation in atomic physics. Its confining potential, uniquely fixed by the underlying conformal symmetry and a holographic mapping to anti-de Sitter spacetime, contains a universal emerging mass scale that governs...
Motivated by the quark-gluon plasma, we develop a simulation method to obtain the spectral function of (Wilson) fermions non-perturbatively in a non-Abelian gauge theory with large gluon occupation numbers. We apply our method to a non-Abelian plasma close to its non-thermal fixed point, i.e., in a far-from-equilibrium self-similar regime, and find mostly very good agreement with perturbative...
Exclusive processes are traditionally described by perturbative hard blocks and
``distribution amplitudes" (DAs), matrix elements of operators of various chiral structure
and twist. One paper (with I.Zahed) calculate instanton contribution to hard blocks, which is
found comparable to perturbative one in few-$GeV^2$ $Q^2$ region of interest. Another paper
aims at comprehensive wave...
An overview of common statistical methods and machine learning approaches deployed at the LHCb experiment will be discussed. Particular focus will be given to recent developments using novel techniques relevant to heavy flavour physics.
The lattice three-gluon vertex in the Landau gauge is
revisited using a large physical volume ∼(8fm)^4 and a large statistical
ensemble. The improved calculation explores the symmetries of the
hypercubic lattice to reduce the statistical uncertainties and to
address the evaluation of the lattice artefacts. In particular we focus
on the low energy behaviour of the vertex and look at...
We present the first determination of the hadronic decays of the lightest exotic JPC=1-+ resonance in lattice QCD. Working with SU(3) flavor symmetry, where the up, down and strange-quark masses approximately match the physical strange-quark mass giving mπ∼700 MeV, we compute finite-volume spectra on six lattice volumes which constrain a scattering system featuring eight coupled channels....
The Born-Oppenheimer approximation provides a description of heavy-quark mesons firmly based on lattice QCD, but its validity is limited to the lightest states lying far below the first open-flavour meson-meson threshold. This limitation can be overcome in the diabatic framework, a formalism first introduced in molecular physics, where the dynamics is encoded in a potential matrix whose...
Spectra with full towers of levels are expected due to the quantization of the string vibrations.
We study a spectrum of flux tubes with static quark and antiquark sources for pure gauge SU(3) lattice QCD in 3+1 dimensions up to a significant number of excitations.
To go high in the spectrum, we specialize in he most symmetric case, the Σ+𝑔, use a large set of operators, solve the...
The evolution of a heavy ion collision passes close to the O(4) critical point of QCD, where fluctuations of the order parameter are expected to be enhanced. Using the appropriate stochastic hydrodynamic equations in mean field close to the
near the pseudo-critical point, we compute how these enhanced fluctuations modify the transport coefficients of QCD and make a phenomenological estimate...
We describe examples of renormalizable field theories where the breaking of chiral symmetry at the UV cutoff leaves behind at low energy dynamically generated elementary particle masses in a way alternative to the Higgs mechanism. In this scenario 1) the scale of the elementary particle masses is set by the RGI scale of the theory 2) masses are kept ``small'' owing to an enhanced chiral...
We study two important properties of 2+1D QCD, namely confinement and Pseudoscalar glueball spectrum, using holographic approach. The confined state of the bounded quark-antiquark pair occurs in the self-coupling dominated nonperturbative regime, where the free gluons form the bound states, known as glueballs. The gauge theory corresponding to low energy decoupled geometry of isotropic...
The "periodic table" of strongly coupled gauge theories remains only sketchily understood. Holography has developed to the point where bottom up constructions can describe the spectrum of individual gauge theories (based on assumptions of their running) including quarks in different representations and higher dimension operators. I highlight the method with a "perfected" version of the AdS...
I will discuss recent lattice calculations of Gegenbauer moments of twist-two light cone distribution amplitudes (LCDAs) of the RQCD collaboration. There has been a lot of progress, in particular regarding taking the continuum limit and the matching to the modified minumal subtraction scheme. LCDAs play an important role in the physics of exclusive processes.
The low-energy QCD, the theory describing the strong interaction, is still missing fundamental experimental results in order to achieve a breakthrough in its understanding. Among these experimental results, the low-energy kaon-nucleon/nuclei interaction studies are playing a key-role, with important consequences going from particle and nuclear physics to astrophysics.
Combining the excellent...
When non-Abelian gauge fields in $SU(3)$ QCD have a line-singularity leading to non-commutability with respect to successive partial-derivative operations, the non-Abelian Bianchi identity is violated. The violation as an operator is shown to be equivalent to violation of the Abelian-like Bianchi identities. Then there appear eight Abelian-like conserved magnetic monopoles of the Dirac type in...
What is the nature of so-called Dark Matter, and does it interact with regular matter except through gravity? For example, direct detection experiments aim to answer this question. Propagating measurements (or constraints) to the fundamental theory requires bridging several scales—from target nucleus to individual nucleons to the level of quarks & gluons and beyond. However, the sheer number...
We present a new tensor network algorithm for calculating the partition function of interacting quantum field theories in 2 dimensions. It is based on the Tensor Renormalization Group (TRG) protocol, adapted to operate entirely at the level of fields. This strategy was applied in Ref.[1] to the much simpler case of a free boson, obtaining an excellent performance. Here we include an arbitrary...
We study exclusive quarkonium production in the dipole picture at next-to-leading order (NLO) accuracy, using the non-relativistic expansion for the quarkonium wavefunction. This process offers one of the best ways to obtain information about gluon distributions at small x, in ultraperipheral heavy ion collisions and in deep inelastic scattering. The quarkonium light cone wave functions needed...
We show that using renormalization-group summation to generate the QCD radiative corrections
to the $\pi-\gamma$ transition form factor, calculated within lightcone sum rules, leads the
strong coupling free of Landau singularities while preserving the QCD form-factor asymptotics.
This enables a reliable applicability of the LCSR method to momenta well below 1~GeV$^2$.
This way, one can use...
Quarkonia are well described by the Schrödinger equation, with a linear confining potential that agrees with lattice QCD. For QED atoms the classical $-α/r$ potential is determined by Gauss’ law. Taking the similarity with QED at face value the confinement scale of QCD should be given by a boundary condition on Gauss’ law.
Temporal gauge $(A^0=0)$ is well suited for bound states defined at...
Understanding the nature of confinement, as well as its relation with the spontaneous breaking of chiral symmetry, remains one of the long-standing questions in high-energy physics. The difficulty of these task stems from the limitations of current analytical and numerical techniques to address nonperturbative phenomena in non-Abelian gauge theories. The situation becomes particularly...
Binary Neutron Star (BNS) mergers provide a rich laboratory for the study of matter at extreme densities and temperatures. In this talk we present the results of state-of-the-art BNS simulations using modern 3-parameter (density, temperature, electron fraction) equations of state (EoSs), with particular focus on behaviour due to temperature and composition dependant effects.
First, we go...
I will review recent developments in rare and radiative kaon decays from the theory side, with emphasis on those modes that are actively analyzed by the experimental collaborations.
We study the transitions between the different color states of a static
quark-antiquark pair, singlet and octet, in a thermal medium. This
is done non-perturbatively exploiting the infinite mass limit of QCD. This study is interesting because it can be used
for future developments within the framework of Effective Field Theories
(EFTs) and because it can be combined with other techniques,...
We study the free energies of individual quarks in a finite volume with suitable boundary conditions to account for their $Z_3$-valued electric flux. In order to demonstrate how 't Hooft's electric fluxes can be used to account for Gauss' law, we first use a $Z_3$-Potts model as an effective Polyakov-loop theory for the heavy-dense limit of QCD at strong coupling, with interfaces to realize 't...
We introduce a Metropolis-Hastings Markov chain for Boltzmann distributions of classical spin systems. It relies on approximate tensor network contractions to propose correlated collective updates at each step of the evolution. We present benchmarks for a wide variety of instances of the two-dimensional Ising model, including ferromagnetic, antiferromagnetic, (fully) frustrated and...
During the late stages of a neutron star binary inspiral finite-size effects come into play, with the tidal deformability of the supranuclear density matter leaving an imprint on the gravitational-wave signal. As demonstrated in the case of GW170817—the first direct detection of gravitational waves from a neutron star binary—this can lead to strong constraints on the neutron star equation of...
In this talk I will present the results of the first numerical investigation of a gauge theory with adjoint and fundamental fermion fields. It corresponds to the heavy scalar limit of supersymmetric QCD and has further applications in composite Higgs models and semiclassical investigations of confinement. I will discuss the interplay of the different fermion representations and relations to...
We study numerically the chromoelectric-chromomagnetic asymmetry of the dimension two $A^2$ gluon condensate as well as the infrared behavior of the gluon propagators at $T\simeq T_c$ in the Landau-gauge $SU(3)$ lattice gauge theory.
We find that a very significant correlation of the real part of the Polyakov loop with the asymmetry as well as with the longitudinal propagator makes it...
We suggest to probe the pion light-cone distribution amplitude, transforming the
dispersion relation for the pion electromagnetic form factor into
an equation between the spacelike form factor
$F_\pi(Q^2)$ and the integrated modulus of the timelike form factor.
For $F_\pi(Q^2)$, the QCD light-cone sum rule in terms of the
pion light-cone distribution amplitudes is used. From this...
We present a comparison among various methods used to extract the spectral functions of S- and P-wave meson states from non-zero temperature NRQCD correlation functions using the FASTSUM anisotropic lattice: the maximum likelihood, Backus Gilbert, and machine learning approaches. We review the common features that can be extracted by all methods and compare the results for masses and widths.
In this talk we present a relativistic and model-independent method to analytically derive electromagnetic finite-size effects beyond the point-like approximation. Structure-dependence appears in terms of physical form-factors and derivatives thereof. The values of these physical quantities can be taken either from experimental measurements or auxiliary lattice calculations. We first apply our...
In this talk I will review the recent developments on the phenomenology and experimental searches for collectivity in small collision systems. For the phenomenology part I will focus on the hybrid approach based on the Color Glass Condensate (CGC) and Hydrodynamics (hydro) simulation [1]. For the experimental part my focus will be on the RHIC small system scan program [2]. I will discuss how...
In this work, we focus on identifying which conditions generate massive stars and how these affect the radii and tidal deformability of intermediate and massive stars. We build equations of state either from realistic models with exotic degrees of freedom or in a model-independent approach, using a functional form of the speed of sound and discuss cross-overs, first-order phase transitions,...
The quantitative understanding of hadron structure holds the key to the interpretation of current and future experiments in particle, hadron and nuclear physics, which provide crucial information for the search for New Physics. In this talk I review the status of lattice QCD calculations of structural properties of the nucleon, focussing on the determination of electromagnetic and axial form...
In lattice QCD simulations, a large number of observables are calculated on each Monte Carlo sample of gauge fields, and their statistical fluctuations are correlated with each other as they share the same background gauge field. By exploiting the correlation, a machine learning regression model can be trained to predict the values of the computationally expensive observables from the values...
The quantized vortices in superfluid confined phase may transform the large orbital momentum generated in heavy-ion collisions to the spin of baryons in the vortex core. The effect emerges only at some threshold angular velocity providing the qualitative explanation for the recent low energy data. The formation of vortex rings is considered as a mechanism of relation between local and global...
Recently a method of measuring static force from the lattice using an insertion of chromoelectric field to an Wilson loop has been proposed to tackle the ambiguities of taking derivative of the static potential. We present the current status of testing the viability of this approach and also expand the calculation for the first time to use gradient flow, which solves the problems with the...
An enhanced phenomenological model that includes isospin-symmetry breaking is presented in this letter. The model is then used in a number of statistical fits to the most recent experimental data for the radiative transitions $V\!P\gamma$ ($V=\rho$, $K^*$, $\omega$, $\phi$ and $P=\pi$, $K$, $\eta$, $\eta^{\prime}$) and estimations for the mixing angles amongst the three pseudoscalar states...
I review attempts at constructing models of partial compositeness from strongly coupled gauge theories.
A few minimality assumptions allow one to isolate a small number of prototypical models.
After presenting the main idea, I discuss a recent proposal to detect a light ALP, predicted in all these models, at the LHCb detector.
The imaginary part of the effective heavy-quark potential can be related to the total in-medium decay width of of heavy quark-antiquark bound states. We extract the static limit of this quantity using classical-statistical simulations of the real-time Yang-Mills dynamics by measuring the temporal decay of Wilson loops. By performing the simulations on finer and larger lattices we are able to...
Critical slowing down and topological freezing are key obstacles to progress in lattice QCD calculations of hadronic properties causing the cost of ensemble generation to severely diverge in the continuum limit. Recently, a class of machine learning techniques known as flow-based models has been successfully applied to produce exact sampling schemes that can circumvent critical slowing down...
We proposed to utilize chiral anomaly [Ref. 1] for the designs of qubits potentially capable of operating at THz frequency and at room temperature. The proposed chiral qubit [Ref. 2] is a microscopic-scale ring made of a chiral semimetal, with the |0⟩ and |1⟩ states corresponding to the symmetric and antisymmetric superpositions of chiral currents circulating along the ring clockwise and...
In this talk I will revisit modified and direct Urca
processes in nuclear matter under conditions that we expect in neutron
star mergers. Nuclear Urca processes have shown to be a potential
significant source of bulk viscosity under merger conditions. I will
explain how a correct relativistic treatment can alter the rates and
the true beta equilibrium significantly, and present a new way...
The axial, scalar, and tensor charges of the nucleon are important observables needed to interpret the results of many experiments and probe new physics. In this talk, I will present our recent lattice QCD calculations of the nucleon charges and discuss systematic uncertainties associated with the excited state contamination.
Hadron production measurement in small collision systems (such as p+Al, p+Au, d+Au, $^3$He+Au) may allow to explore the minimal conditions for the quark-gluon plasma formation. Such research has become particularly crucial with the observation of the light hadrons collective behavior in small collision systems. Among the large variety of light hadrons, φ-meson is of particular interest...
We analyse the properties of thermal monopoles in the high temperature phase of QCD with N_f = 2+1 flavours and physical quark masses. In particular, we determine the temperature where monopoles show condensation properties similar to those already studied in pure gauge Yang-Mills theories and related to the onset of confinement, comparing it with the temperature where chiral symmetry...
In quantum electrodynamics with charged chiral fermions, a background
electric field is the source of the chiral anomaly that can manifest
itself through the creation of a chirally imbalanced state of
fermions. This chiral state is realized through the production of
entangled pairs of right-moving fermions and left-moving antifermions
(or viceversa, depending on the orientation of the...
The maturity era of lattice quantum field theory simulations brings in ample potential both to explore theories beyond QCD, and to investigate the qualitative workings of QCD by opening up the parameter space. We will focus on studying hadronic interactions and weak decays as a function of the number of colours, with four dynamical quark flavours. This shines light on classic problems such as...
We study the machine learning techniques applied to the lattice gauge theory's critical behavior, particularly to the confinement/deconfinement phase transition in the SU(2) and SU(3) gauge theories. We find that the neural network, trained on lattice configurations of gauge fields at an unphysical value of the lattice parameters as an input, builds up a gauge-invariant function, and finds...
Heavy quark transport coefficients calculated from first-principles QCD are a crucial input for transport models. Utilizing the heavy quark limit, we will discuss the results of a novel approach to nonperturbatively estimate the heavy quark diffusion coefficient in a hot gluonic medium from gradient-flowed color-electric correlators on the lattice. Unlike others, this approach can be extended...
We present the results concerning analytic (3+1)-dimensional inhomogeneous and topologically nontrivial pion systems hosting topologically stable baryons. This phase, relevant for the core of compact stars featuring a pion condensed core, is discussed within two-flavor leading order chiral perturbation theory.
Precise knowledge of the thermodynamic properties of zero-temperature, high-density quark matter (QM) can constrain the neutron-star-matter equation of state (EOS), even at much lower densities. However, current bounds on this QM EOS suffer from rather large uncertainties stemming from renormalization-scale dependence. In this talk, I will lay out how to improve the dense QM EOS beyond N2LO,...
We discuss the effects of rotation on confining properties of gauge theories focusing on compact electrodynamics in two spatial dimensions as an analytically tractable model. We show that the rotation leads to a deconfining transition at finite temperature starting from a certain distance from the rotation axis. We argue that the uniformly rotating confining system possesses, in addition to...
Within General Relativity there is a maximum latent heat for a first order phase transition that a neutron star can support, the Seidov limit. If neutron-star matter exceeds it, the transition to the presumed exotic phase will not be complete before the star undergoes gravitational collapse.
However, this limit should generally be different in theories of modified gravity, that are to be...
The Casimir energy and profile of the QCD flux-tube are discussed within the framework of Lüscher-Weisz (LW) string action with two boundary terms. We perform our numerical simulations on the 4-dim pure SU(3) Yang-Mills lattice gauge theory at finite temperature. The static quark-antiquark ($Q\bar{Q}$) potential is calculated using link-integrated Polyakov loop correlators. In general, we...
I will discuss the muon anomalies that have been persisting in data in the recent years, namely the muon g-2 and the lepton flavour non-universality in B decays, in the context of strongly coupled theories. I will show that these anomalies are natural in composite theories of the Higgs sector of the Standard Model. In particular, the characteristic scale of 2 TeV emerging from the muon g-2...
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is an upgrade of the B factory facility at KEK in Tsukuba, Japan. The experiment began operation in 2019 and aims to record a factor of 50 times more data than its predecessor. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First...
The unsupervised search for overdense regions in high-dimensional feature spaces, where locally high population densities may be associated with anomalous contaminations to an otherwise more uniform population, is of relevance to applications ranging from fundamental research to industrial use cases. Motivated by the specific needs of searches for new phenomena in particle collisions, we...
We investigate the single transverse-spin asymmetry with a $sin(2\phi-\phi_S)$ modulation in the pion-induced Drell-Yan process within the theoretical framework of the transverse momentum dependent (TMD) factorization. The asymmetry is contributed by the convolution of the Boer-Mulders function and the transversity. We adopt the model results for the distributions of the pion meson and the...
With non-perturbative lattice calculations we investigate the finite-temperature confinement transition of a composite dark matter model. We focus on the regime in which this early-universe transition is first order and would generate a stochastic background of gravitational waves. Future searches for stochastic gravitational waves will provide a new way to discover or constrain composite dark...
Holographic techniques are particularly fit to analyzing matter at extreme conditions where QCD matter is strongly coupled. Combining predictions of the holographic model with state-of-the-art effective field theory models of nuclear matter, I construct a family of feasible "hybrid" equations of state which cover both the quark matter and nuclear matter phases. The model predicts, among other...
In this work, we analyzed a recent proposal to detect SU(N) continuum Yang-Mills sectors labeled by center vortices, inspired by Laplacian-type center gauges in the lattice. Initially, after the introduction of appropriate external sources, we obtained a rich set of sector-dependent Ward identities, which can be used to control the form of the divergences. Next, we were able to show the...
The nature of the three narrow hidden-charm pentaquark $P_c$ states, i.e., $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$, is under intense discussion since their discovery from the updated analysis of the process $\Lambda_b^0\to J/\psi p K^-$ by LHCb. We employ an coupled-channel approach to study the $P_c$ states observed by LHCb Collaborations in the molecuar picture, in which the $P_c$ states...
Matrix inversion problems are often encountered in experimental physics, and in particular in high-energy
particle physics, under the name of unfolding. The true spectrum of a physical quantity is deformed by
the presence of a detector, resulting in an observed spectrum. If we discretize both the true and observed
spectra into histograms, we can model the detector response via a matrix....
Charged particle multiplicity distributions in positron-proton deep inelastic scattering at a centre-of-mass energy $\sqrt{s}=319$ GeV are measured. The data are collected with the H1 detector at HERA corresponding to an integrated luminosity of $136$ pb$^{-1}$. Charged particle multiplicities are measured as a function of photon virtuality $Q^2$, inelasticity $y$ and pseudorapidity $\eta$ in...
Decomposition of SU(2) gauge field into monopole and monopoleless components is studied in SU(2) gluodynamics and in QC_2D with nonzero quark chemical potential after fixing MA gauge. For both components we calculate respective static potential and compare their sum with the nonabelian static potential. We demonstrate good agreement in the confinement phase and discuss the implications of our results.
Effective Field Theories (EFTs) organized as derivative expansions are controllable as long as the energy of the interacting particles remains small, as they do not respect exact elastic unitarity. This limits their predictive power towards new physics at a higher scale if small separations from the Standard Model are found at the LHC or elsewhere.
This is exemplified by ChPT: though...
In this talk I will describe dark sectors made of non-abelian gauge theories with fermions neutral under the Standard Model. This leads to accidentally stable Dark Matter candidates that can be populated minimally through gravitational interactions. In the pure glue scenario DM is the lightest glueball while adding light fermions the lightest pion and baryon are the DM candidates.
Despite the...
Calculating analytic properties of Euclidean propagators is a demanding task, in particular if one considers non-perturbative approaches, such as Dyson-Schwinger equations. At the same time, once calculated in the complex domain, these correlators provide valuable insights into various properties associated with the proagating degree of freedom, and can serve as input to bound state equations....
We study the quark-gluon vertex in the limit of vanishing gluon momentum using lattice QCD with 2 flavors of O(a) improved Wilson fermions, for several lattice spacings and quark masses. We fi?nd that all three form factors in this kinematics have a signi?cant infrared strength, and
that both the leading form factor ?1, multiplying the tree-level vertex structure, and the scalar,
chiral...
In addition to the well known-sign problem, methods currently used to study finite baryon density lattice QCD suffer from additional uncontrolled systematics, coming e.g. from the analytic continuation problem one faces with the Taylor or imaginary chemical potential methods. We formulate and test a new method - sign reweighting - that works directly at finite chemical potential and is free...
In this talk I will provide a brief review of the different results and approaches used in estimating the contributions to the anomalous magnetic moment of the muon, with emphasis on the hadronic contributions. The presentation will follow the review released by the Muon g-2 Theory Initiative.
Working in sectors of large global charge leads to important simplifications when studying strongly coupled CFTs.
In this talk I will introduce the large-charge expansion via the simple example of the O(2) model and apply it in a number of other situations displaying a richer structure, such as asymptotically safe theories and walking dynamics.
We extract the diffusion coefficient $\kappa$ and the resulting momentum broadening $\langle p^2 \rangle$ of a heavy quark embedded in a far-from-equilibrium gluon plasma using classical statistical lattice simulations. We find several features in the time dependence of the momentum broadening: a short initial rapid growth of $\langle p^2 \rangle$, followed by linear growth with time due to...
I will give a brief review on the theory of jet quenching and discuss some recent progress toward measuring quark and gluon jet modification in heavy-ion collisions.
One of the main limitations in particle physics analyses with ML-based selection is the understanding of the implications of systematic uncertainties. The usual approach being the training using samples without systematic effects and estimating their contribution to the magnitudes measured on modified test samples. We propose here a method based on data augmentation to incorporate the...
String tension is one of the characteristic quantity in confining gauge theories. In SU(N) gauge theories, there is a center symmetry, or $\mathbb{Z}_N$ 1-form symmetry, which acts on the test quarks, and this is the symmetry which controls the spectral properties of confining strings in the infrared regime. This is sometimes called as an $N$-ality rule.
In this talk, I will talk about some...
We present the unified equation of state with induced surface tension (IST) that reproduces the nuclear matter properties, fulfills the proton flow constraint, provides a high-quality description of hadron multiplicities created during the nuclear-nuclear collision experiments, and is equally consistent with NS observations. Obtained tidal Love numbers are in full agreement with the...
We discuss vortex solutions in the non-Hermitian parity-time-symmetric relativistic model with two interacting scalar complex fields. In the London limit, the vortex singularities in different condensates experience dissipative dynamics unless they overlap. At finite quartic couplings, the vortices appear in the PT-symmetric regions with broken U(1) symmetry. We find the phase diagram of the...
A complete theoretical analysis of the $C$-conserving semileptonic decays $\eta^{(\prime)}\to\pi^0l^+l^-$ and $\eta^\prime\to\eta l^+l^-$ ($l=e$ or $\mu$) is carried out within the framework of the Vector Meson Dominance (VMD) model. An existing phenomenological model is used to parametrise the VMD coupling constants and the associated numerical values are obtained from an optimisation fit to...
The statistical significance that characterizes a discrepancy
between a measurement and theoretical prediction is usually
calculated assuming that the statistical and systematic
uncertainties are known. Many types of systematic uncertainties
are, however, estimated on the basis of approximate procedures and
thus the values of the assigned errors are themselves uncertain.
...
Statistical models are a powerful tool for investigation of complex system's behaviour. Most of the models considered in the literature are defined on regular lattices with nearest neighbour interactions. The models with nonlocal interaction kernels have been less studied. In our study we investigate an example of such a model - the nonlocal $q$-color Potts model on a random $d=2$ lattice....
I present the results of a systematic investigation of the possible locations for the neutron star special point (SP), a unique feature of hybrid neutron stars in the mass-radius. The study is performed within the two-phase approach where the high-density (quark matter) phase is described by the constant-sound-speed (CSS) equation of state (EoS) and the nuclear matter phase around saturation...
We have developed a self-consistent theoretical approach to study the modification of the properties of heavy mesons in hot mesonic matter which takes into account chiral and heavy-quark spin-flavor symmetries. The heavy-light meson-meson unitarized scattering amplitudes in coupled channels incorporate thermal corrections by using the imaginary-time formalism, as well as the dressing of the...
Model-independent short-distance constraints allow for a reduction of theoretical uncertainties associated to the analytic evaluation of Hadronic Light by Light contributions to muon g-2. In this talk we focus on the region where the three loop virtualities are large. Even when the fourth photon leg is soft, we show how a precise Operator Product Expansion can be applied in that region. The...
When investigating confinement in the Coulomb gauge on the lattice, one encounters some difficulties in devising a suitable definition of the dispersion relations for Wilson fermions. In this talk we will discuss a solution to this problems based on a redefinition of the lattice physical momentum of the fermion.
We have recently completed the coupled dispersive analysis of $\pi K$ pi pi -> K anti-K data.
We show that just fitting data fails to satisfy the dispersive representation and leads to inconsistencies with threshold sum-rules as well as unreliable resonance parameterizations.
Our main result is a set of constrained fits to data that satisfy 16 dispersion relations of different kinds and...
Evaluating extremely low p-values with importance sampling techniques in discovery-oriented HEP analyses.
Many results in current particle physics studies are derived using asymptotic approximations to calculate the p-value (or the significance) of the hypothesis tested. It is difficult to ensure to which extent the requirements for these approximations are valid in cases where the number...
The broken inversion symmetry of underlying crystals of non-centrosymmetric superconductors gives rise to new nontrivial phenomena, such as magnetoelectric effects and helical phases. We study non-centrosymmetric superconductor using the Ginzburg-Landau effective model supplemented with a parity-odd Lifshitz term. We show that these parity-odd superconductors possess knotted solitons in a...
Taking into account experimental data, theoretical calculations and neutron star observations to constrain the equation of state several properties of neutron stars will be discussed, in particular: possible properties of hybrid stars, the influence of hyperonic degrees of freedom on the cooling of neutron stars, the presence of light clusters in the warm equation of state and the effect of...
We revisit previous determination of the strong coupling constant from moments
of quarkonium correlators in (2+1)-flavor QCD. We use
previously calculated moments obtained with Highly Improved Staggered
Quark (HISQ) action for five different quark masses and several lattice spacings.
We perform a careful continuum extrapolations of the moments and from the comparison
of these to the...
In recent years, significant progress in the calculation of the HLbL contribution to the anomalous magnetic moment of the muon has been achieved both with data-driven methods and in lattice QCD. In the talk I will discuss current developments aimed at controlling HLbL scattering at the level of 10%, as required for the final precision of the Fermilab E989 experiment.
The Muon g-2 Experiment (E989) at Fermi National Accelerator Lab- oratory (FNAL) has measured the muon anomalous precession frequency (a_μ) in its first physics run in 2018 with a precision of 0.46 parts per million. The anomalous precession frequency was measured using the in- tensity variation of positrons from the decay of polarized positive muons circulating around a storage ring. The...
The concept of lepton universality, where the muon and tau particles are simply heavier copies of the electron, is a key prediction in the Standard Model (SM). In models beyond the SM, lepton universality can be naturally violated with new physics particles that couple preferentially to the second and third generation leptons. Over the last few years, several hints of lepton universality...
I will discuss the properties of some spatially inhomogeneous phases in hadronic matter at finite densities
The $SU(2)$ Lattice Gauge Theory in $(2+1)$ dimensions is a perfect laboratory to study the fine details of the confining interquark potential. In this talk I will first discuss a few important properties of the effective string theory and then I will compare its predictions with the results of some recent high precision montecarlo simulations of the $SU(2)$ LGT, looking for possible...
High statistics samples from modern experiments triggered an essential work on revisiting theoretical models and tools applied to analyze the resonance phenomena of QCD.
In this talk, I will discuss two exotic-resonance candidates, $a_1(1420)$ and $\pi_1(1600)$ cleared up over the last few years using data of the COMPASS experiment.
With our recent analysis [hep-ph:2006.05342], the...
Symmetry is a key concept in physics. Some symmetries exist however only in the classical world and can not be realized in the quantum theory. When this happens we speak of a (quantum) anomaly. The most prominent examples are the triangle anomalies arising the quantum field theory of chiral fermions. In particle physics they explain the short lifetime of the neutral pion, give rise to...
Hadron spectroscopy is an important tool to study quark dynamics by various hadron properties such as resonance mass, spin, parity, angular momentum, etc. In addition to these, magnetic moments and various possible decay channels are of keen interest to know the intrinsic interaction. A potential model is used to determine these properties for a particular hadron, and the results are compared...
I will present our work on the application of a combination of soft collinear effective theory and non-relativistic QCD to observables in quarkonium production and decay that are sensitive to soft gluon radiation, in particular measurements that are sensitive to small transverse momentum. Ultimately the aim is to use this approach to study quarkonium production in hadronic collisions at small...
The anomalous currents of two and three-flavor chiral nuclear matter in the presence of chiral imbalance are computed, using recently developed methods based on differential geometry techniques exploiting generalized transgression, which facilitates the evaluation of both the equilibrium partition function and the covariant currents. The constitutive relations for both the broken and unbroken...
In this talk I present our progress on lattice gauge equivariant convolutional neural networks (L-CNNs). These new types of neural networks are a variant of convolutional neural networks (CNNs) which exactly preserve lattice gauge symmetry. By explicitly accounting for parallel transport in convolutions and allowing for bilinear operations inside the network, we show that L-CNNs can be used to...
rest at LEAR, the CERN-Munich multipoles for $\pi\pi$ elastic scattering, the $S$-wave from BNL data on $\pi\pi$ scattering into $K_SK_S$, and from GAMS data on $\pi\pi\to \pi^0\pi^0, \eta\eta$, and $\eta\eta'$. The analysis reveals the existence of ten scalar isoscalar resonances. The resonances can be grouped into two classes: resonances with a large SU(3) singlet component and those with
a...
Chiral perturbation theory is a low-energy effective theory for QCD that gives
model-independent prediction in its region of validity. In this talk, I will present recent progress in two and three-flavor chpt at finite isospin density.
This is includes thermodynamic quantities, quark, and pion condensates, and phase diagrams, all calculated at next-to-leading order. The results are compared...
Motivated by the experimental patterns of lepton-universality breaking, we present a simple strategy based on ratios of leptonic and semileptonic B decays which decouple the CKM elements $|V_{ub}|$ and $|V_{cb}|$ from the short-distance coefficients of (pseudo)-scalar, vector and tensor operator contributions associated with $b \rightarrow u$ and $b \rightarrow c$ transitions. We illustrate...
The vacuum of quantum chromodynamics has an incredibly rich structure at the confinement scale, which is intimately connected with the topology of gauge fields, and put to a stringent test by the strong CP problem. We investigate the long distance properties of the theory in the presence of a topological $\theta$ term. This is done on the lattice, using the gradient flow to isolate the long...
The crucial role played by the underlying symmetries of high energy physics and lattice field theories calls for the implementation of such symmetries in the neural network architectures that are applied to the physical system under consideration. In this talk we focus on the consequences of incorporating translational equivariance among the network properties, particularly in terms of...
We point out a novel configurations in holographic QCD, allowing baryons to coexist with fundamental quarks. The resulting phase is a dual realization of quarkyonic matter, which is predicted to occur in QCD at a large number of colors, and possibly plays a role in real-world QCD as well. We find that holographic quarkyonic matter is chirally symmetric and that, for large baryon chemical...
In this talk we will present several quarkonium polarization measurements that the CMS collaboration has made, in the bottomonium and charmonium families. Emphasis will be given to the most recent measurements, including the result on the chi_c1 and chi_c2 polarizations.
New data from BESIII and LHCb indicate the existence of two hidden charm, open strangeness resonances, dubbed Zcs(3985) and Zcs(4003). Their quasi-degeneracy reproduces, in the strange quark sector, the situation observed with X(3872) and Zc(3900) in the u,d quark sector. The Zcs resonances neatly fit into two broken SU(3)f symmetry nonets with JP = 1+ and opposite charge-conjugation. The mass...
Suspended graphene provides an example of strongly correlated chiral fermions in 2+1D, and the logarithmic renormalization of the Fermi velocity in the infrared limit is one of the most prominent consequences of electron-electron interaction. For the first time, we could directly reproduce this effect in fully non-perturbative Quantum Monte Carlo (QMC) calculations using as large as 102x102...
In relativistic nuclear collisions the production of hadrons with light (u,d,s) quarks is quantitatively described in the framework of the Statistical Hadronization Model (SHM). Since charm quarks are dominantly produced in initial hard collisions but interact strongly in the hot fireball, charmed hadrons can be incorporated into the SHM by treating charm quarks as 'impurities' with thermal...
We solve the Lindblad equation describing the Brownian motion of a Coulombic heavy quark-antiquark pair in a strongly coupled quark-gluon plasma using the highly efficient Monte Carlo wave-function method. The Lindblad equation has been derived in the framework of pNRQCD and fully accounts for the quantum and non-Abelian nature of the system. The hydrodynamics of the plasma is realistically...
In the context of warped five-dimensional models formulated to understand the physics beyond the Standard Model (SM), we will discuss the prediction of a continuum of Kaluza-Klein modes, on top of the SM zero modes, with different mass gaps for all particles: gauge bosons, fermions, graviton, radion and Higgs boson. In particular, we will study the existence of resonance effects in gauge...
Since the first positive measurement of the Λ-hyperon global spin polarization in heavy-ion collisions by STAR in 2017, the understanding of the nature of this phenomenon is one of the most intriguing challenges for the community. As relativistic fluid dynamics celebrates multiple successes in describing collective dynamics of the QCD matter in such reactions, the natural question arises...
In this work, we shall analyze mixed ensembles formed by percolating oriented
and nonoriented center-vortices in three and four dimensions. In particular, we suggest that the inclusion of the natural interactions and possible matching rules are responsible for the emergence of topological solitons that accommodate an asymptotic Casimir scaling law and the observed flux tube profiles.
Results for the ground states and excited states of glueballs in Yang-Mills theory with $J^{\pm+}$, J=0,1,2,3,4, from Bethe-Salpeter equations are presented. The input comes from parameter-free Dyson-Schwinger calculations of the propagators and vertices. We compare with the corresponding lattice results and add some excited states to the known spectrum.
The simulation-based inference is a powerful approach that can deal with various challenges ranging from discovering hidden properties to simulation algorithms tuning and optimising device configurations. Such methods as evolutionary algorithms or Bayesian optimisation usually help to address those challenges. However, those approaches rely on assumptions that might not hold. Recently, a...
It depends: While we find within holography that the lifetime of the magnetic field for collider energies like the ones achieved at RHIC is long enough to build up the chiral magnetic current, the lifetime of the magnetic field at LHC seems to be too short. We study the real time evolution of the chiral magnetic effect out-of-equilibrium in strongly coupled holographic gauge theories. We...
A purely data-driven fit of J/psi, psi(2S) and chi_c1,2 measurements reported by ATLAS and CMS, including the recently measured chi_c decay distributions, constrains the polarization of the directly produced J/psi mesons to a remarkably small and pT-independent value: lambda_theta = 0.04 +- 0.06. If this observation of seemingly unpolarized quarkonium production is confirmed by more precise...
Experimental measurements of multiplicity fluctuations are used to extract information about the properties of the quark-gluon plasma and transition to the hadron gas phase in heavy-ion collisions. In particular, the event-by-event fluctuations of conserved quantities within a fixed rapidity range can be related to thermodynamic properties of the medium, allowing for direct comparison to...
Strong magnetic fields are relevant for both systems where QCD matter can be studied in practice - heavy ion collisions and neutron stars. The ground state of QCD at zero temperature, in sufficiently strong magnetic fields and at moderate baryon densities was recently shown to carry a crystalline condensate of neutral pions: the chiral soliton lattice. This phase of matter might be relevant...
The spinodal instability is a prime signal for the first-order phase transition with negative speed of sound squared $cs^2$ in the Quantum-ChromoDynamics phase diagram relevant for the RHIC energy scan. In recent studies [1,2], one evolves planar unstable black branes dual to a plasma with a first order phase transition subject to the spinodal instability. Near a critical...
I summarize recent work pointing towards the existence of a universal holographic light-front wavefunction for light mesons and nucleons. This holographic wavefunction, which describes simultaneously a bound state in light-front QCD and the propagation of string modes in a dilaton-modified 5-dimensional anti de Sitter spacetime, is a specific realization of the gauge-gravity duality. The...
Confinement remains one the most interesting and challenging nonperturbative phenomenon in non-Abelian gauge theories. Recent semiclassical (for $SU(2)$) and lattice (for QCD) studies have suggested that confinement arises from interactions of statistical ensembles of instanton-dyons with the Polyakov loop. In this talk, I will present recent work which has extended the study of semiclassical...
Accurate and fast simulation of particle physics events is crucial for the high-energy physics community. Simulating particle interactions with the detector is both time consuming and computationally expensive. With its proton-proton collision energy of 13 TeV, the Large Hadron Collider is uniquely positioned to detect and measure the rare phenomena that can shape our knowledge of new...
We compute the color singlet and color octet NRQCD long-distance matrix elements for inclusive production of P-wave quarkonia in the framework of pNRQCD. In this way, the color octet NRQCD long-distance matrix element can be determined without relying on measured cross section data, which has not been possible so far. We obtain inclusive cross sections of χcJ and χbJ at the LHC, which are in...
It is known since long that hydrodynamic flow in the directions of an external gravitational force and gradient of temperature are related to each other. We consider generalizations to the cases of higher orders in hydrodynamic expansion and/or to higher orders in acceleration. We demonstrate in particular that the vortical effect in presence of gravity is reproduced via the equivalence...
A principal element of unified description of strongly interacting matter within the effective theories corresponds to hadronization of chiral quark models and incorporation of the confinement mechanism into them, manifesting the switching between hadron and quark degrees of freedom. Such an approach is formulated based on a relativistic density-functional motivated by the string-flip model....
We discuss the theoretical implications of the recent discovery of CP violation in two-body charm decays at LHCb. The 2019 breakthrough follows the first discovery of CP violation in kaon decays in 1964 and in beauty decays in 2001. We illustrate that charm physics has the potential for the discovery of physics beyond the Standard Model and will teach us also more about non-perturbative low-energy QCD.
We will discuss thermal modifications of charmonium and bottomonium spectral properties in a hot gluonic medium from continuum extrapolated lattice results. The dissociation temperatures of quarkonia as well as charm and bottom quark diffusion coefficients are presented in the temperature region from 1.1$T_c$ to 2.25$T_c$ in the quenched approximation with valence quarks tuned to physical...
In this talk, we introduce machine learning techniques for lattice QCD. Lattice QCD is one of the most successful methodologies of quantum field theory, which provides us quantitative values of QCD. On the other hand, machine learning enables us to treat big structured data. In particular, neural networks are widely used since it has universal approximation property while it cannot be exact....
In recent years, a significant theoretical effort has been made towards a dynamical description of quarkonia inside the Quark-Gluon Plasma (QGP), using the open quantum systems formalism. In this framework, one can get a real-time description of a quantum system (here the quarkonium) in interaction with a thermal bath (the QGP) by integrating out the bath degrees of freedom and studying the...
AMBER is a newly proposed fixed-target experiment at the M2 beam line of the SPS, devoted to various fundamental QCD measurements, with a Proposal very recently approved by the CERN Research Board for a Phase-1 program and a Letter of Intent made public for a longer term program.
Such an unrivalled installation would make the experimental hall EHN2 the site for a great variety of measurements...
We solve the Lindblad equation describing the Brownian motion of a Coulombic heavy quark-antiquark pair in a strongly coupled quark-gluon plasma using the highly efficient Monte Carlo wave-function method. The Lindblad equation has been derived in the framework of pNRQCD and fully accounts for the quantum and non-Abelian nature of the system. The hydrodynamics of the plasma is realistically...
I will briefly review the current status of transverse-momentum-dependent (TMD) factorization and related frameworks, focusing on its applicability at the LHC.
