Conveners
Parallels Track B: Monday I
- Hagop Sazdjian (Université Paris-Saclay, IJCLab, Orsay)
Parallels Track B: Monday II
- Hagop Sazdjian (Université Paris-Saclay, IJCLab, Orsay)
Parallels Track B: Tuesday I
- Ignazio Scimemi (Universidad Complutense Madrid)
Parallels Track B: Tuesday II
- Ignazio Scimemi (Universidad Complutense Madrid)
Parallels Track B: Thursday I
- Jose R. Pelaez Sagredo (Universidad Complutense)
Parallels Track B: Thursday II
- Jose R. Pelaez Sagredo (Universidad Complutense)
Parallels Track B: Friday I
- Felipe Jose Llanes-Estrada (Univ. Complutense de Madrid)
Parallels Track B: Friday II
- Felipe Jose Llanes-Estrada (Univ. Complutense de Madrid)
The increasing accuracy in the experimental measurements of several hadronic observables related to weak processes, which in many cases is smaller than $\mathcal{O}(1\%)$, requires the inclusion in theoretical calculations of subleading corrections that were neglected so far. Over the past decade isospin breaking effects due to electromagnetic interactions and to the up-down quark mass...
I will present some recent state-of-the-art lattice QCD results revealing partonic structures of pion and kaon. These results will include valance parton distribution function of pion, pion distribution amplitude as well as electromagnetic form factor of kaon at large momentum transfers.
We have calculated the axial-vector form factors for the hyperon semileptonic decays $B_i \rightarrow B_f l \bar{\nu}$ in the chiral constituent quark model ($\chi$CQM). The decays considered here are the strangeness changing as well as strangeness conserving semileptonic decays of the hyperons. The conventional dipole form of parametrization has been used to analyse the $Q^2$ dependence of...
The last two decades have witnessed the discovery of a myriad of new and
unexpected hadrons. The future holds more surprises for us, thanks to
new-generation experiments. Understanding the signals and determining
the properties of the states requires a parallel theoretical effort. To
make full use of available and forthcoming data, a careful amplitude
modeling is required, together...
The flow of information in high-energy collisions has been recently investigated by various groups. Entanglement entropy of the proton becoming classical information entropy of pdfs, jet splitting affecting entropy, or the entropy in hadron decays have already been reported in the literature. Here we examine aspects of fragmentation functions in this context, including their entropy as...
We investigated the two scalar glueball
scattering and the possible emergence of a bound state,
that we call glueballonium. The scalar glueball, the lightest particle of the
YM sector of QCD, has a lattice predicted mass of about
$m_{G}\simeq1.7$ GeV. We performed this study in the context of a
widely used dilaton potential, that depends on a single dimensionful parameter $\Lambda_G$....
Using the approach based on conformal symmetry we calculate the two-loop coefficient function for the axial-vector contributions to two-photon processes in the MS¯ scheme. This is the last missing element for the complete next-to-next-to-leading order (NNLO) calculation of the pion transition form factor γ*γ→π in perturbative QCD. The corresponding high-statistics measurement is planned by the...
Recent years have brought a breakthrough for calculations of partonic distributions on a Euclidean lattice. In this talk, I will discuss our progress in extracting generalized parton distributions (GPDs) from the quasi-distribution approach. I will present both the leading-twist GPDs and our exploratory studies of selected twist-3 cases.
We perform lattice QCD simulations in order to calculate nucleon four-point functions, which can be used to extract Mellin moments of double parton distributions (DPDs). In this first study, we consider the first DPD Mellin moment of the unpolarized proton. We employ an $n_f = 2+1$ ensemble with pseudoscalar masses of $m_\pi = 355~\mathrm{MeV}$ and $m_K = 441~\mathrm{MeV}$, the results are...
In this talk I will discuss how one can be more differential in
event-shape distributions by measuring the angle defined by the thrust axis
and the beam. As was shown in an earlier publication, the angular
dependence can be parametrised in terms of the well-known angular-averaged
cross section and the so called “angular” distribution. I will show that,
even though for jets initiated by...
An array of high-priority HEP measurements are increasingly limited by the
precision of nucleon and nuclear parton distribution functions (PDFs) and
related quantities. Curiously, as the accuracy of perturbative QCD
calculations steadily improves, there is a growing need for parallel
enhancements to control a variety of nonperturbative QCD, electroweak, and
methodological effects in...
Factorization theorems are known to be extremely powerful tools in high-energy particle physics. Processes like SIDIS, Drell-Yan vector-boson production, Higgs-boson production through gluon fusion and $e^+e^-$ to jets and/or hadrons are just some examples of processes that have been thoroughly investigated by applying rigorous factorization formulae. Furthermore, if in these processes the...
After a brief historical review of the $\alpha_s$ determination from tau decay and the difficulty of dealing with Duality Violations and the associated asymptotic nature of the OPE which was present in previous analyses, I will describe a new determination of the strong coupling constant based on an improved vector isovector spectral function. This spectral function results from combining...
Pinched Borel-Laplace sum rules are applied to ALEPH $\tau$-decay data. For the leading-twist ($D=0$) Adler function a renormalon-motivated extension is used, whose coefficient at $(\alpha_s/\pi)^5$ is taken according to the estimate $d_4=275 \pm 63$. Two terms of dimension $D=6$ are included in the truncated OPE ($D \leq 6$), in order to enable cancellation of the corresponding renormalon...
In my talk, I will present a data-driven coupled-channel analysis of the isoscalar S-wave {$\pi\pi,KK$} scattering using the partial-wave dispersion relations. The central result is the Omnes matrix, which does not have left-hand cuts, and therefore serves as the crucial input needed to study the final state interactions of any hadron processes where the system of two pions (and two kaons)...
In many physical applications, bound states and/or resonances are observed, which raises the question whether these states are elementary or composite. This talk deals with the calculation of the degree of composition (X) of bound or resonant states. We fist review the “classical” formalism to afford this problem for a bound state in nonrelativistic (NR) Quantum Mechanics (QM). Then, we show...
The $\rm{f}_{0}$(980) was observed years ago in $\pi\pi$ scattering experiments. Despite a long history of experimental and theoretical research, the nature of such a short-lived resonance is not understood and there is no consensus on its quark content.
The $\rm{f}_{0}$(980) resonance is measured by ALICE using the $\pi\pi$ decay channel. In this contribution, the multiplicity dependence of...
The standard model provides for the existence of hybrid states that contain a gluon in addition to the quark and the antiquark. The $\pi_1(1600)$ and the recently observed $\eta_1(1855)$ are examples of such exotic mesons. In the present work, we study the masses and the two-body decays of the members of the lightest hybrid nonet with quantum numbers $1^{-+}$ using a Lagrangian invariant under...
We will report on recent works featuring the parton distribution functions (DFs) of pion-like systems at experimental scales, following an approach which relies on the assumption that there is an effective charge defining an evolution scheme for DFs that is all-orders exact. Within this framework, strict lower and upper bounds on all Mellin moments of the valence-quark DFs are derived....
The spectrum of QCD is expected to contain, besides bound states of quarks, also bound states of gluons. These glueballs can mix with other states that have the same quantum number. For pure Yang-Mills theory, on the other hand, glueballs are the only physical degrees of freedom which makes the picture much clearer. Using state-of-the-art, parameter-free solutions for the propagators and...
We discuss the status of both conventional and unconventional mesons between 1 and 2 GeV by using hadronic models that describe their masses, strong, and radiative decays. Various conventional quark-antiquark states are considered: some of them, such as the tensor mesons with $J^{PC}=2^{++}$ and mesons with $J^{PC}=3^{--}$, form well established nonets, while other, such as the axial-tensor...
The quark-gluon vertex is one of the basic building blocks of the strong interaction. It is an essential ingredient in functional approaches to nonperturbative quantum chromodynamics (QCD). In the literature, many studies of hadron phenomenology in the Schwinger-Dyson Equation framework have been carried out using the rainbow-ladder truncation, where the quark-gluon vertex is approximated by...
A metastable phase has important physical implications, since it may form vacuum bubbles detectable experimentally. It is well known that, due to spontaneous chiral symmetry breaking, there are two, or more, different QCD vacua. In the chiral limit, in the true vacuum, the pseudoscalar ground states are Goldstone bosons. The chiral invariant vacuum (at the top of the "Mexican hat") is an...
Observation of the scalar glueball, evidence for the tensor glueball, how to search for the pseudoscalar glueball
The scalar glueball is observed in a coupled-channel analysis of the $S$-wave amplitude from BESIII data on radiative $J/\psi$ decays and further data. Ten scalar isoscalar resonances were required to fit the data. Five of them were interpreted as mainly singlet, five as...
The excitation spectrum of light mesons; which are composed of up, down, and strange quarks; allows us to study QCD at low energies. While the non-strange light-meson spectrum is al- ready mapped out rather well, many predicted strange mesons have not yet been observed experimentally and many potentially observed states still need further confirmation. Hence, the strange-meson spectrum still...
I will review the present status and recent progress on light-meson scattering analyses, by means of dispersive or analytic methods. The recent application of these model independent techniques have settled the controversy about the existence and parameters of long debated resonances. I will thus review the status and recent changes on our knowledge about the resonances observed in these...
