Mon·Nov 8, 2021Monday·November 8, 2021

1. 01*

   Generalized parton distributions of the proton from lattice QCD

   Constantia Alexandrou🇨🇾 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Kyriakos Hadjiyiannakou🇨🇾 · Karl Jansen🇩🇪 · Aurora Scapellato🇵🇱 · Fernanda Steffens🇩🇪

   Generalized parton distributions (GPDs) are among the most fundamental quantities for describing the internal structure of hadrons. In this work, we present results on isovector GPDs of the proton obtained within lattice Quantum Chromodynamics. We use the quasi-distribution formalism and perform the calculations on an ensemble of $N_f=2+1+1$ twisted mass fermions, with pion mass $M_{\pi }=260$~MeV and lattice spacing $a\simeq 0.093$~fm. Results are presented for unpolarized, helicity, and transversity GPDs at zero and nonzero skewness with controlled statistical uncertainties. Comparisons with their forward limit show qualitative features anticipated from model calculations.

   hep-latPoS(2022)·10 citations
2. 02*

   Thermal QCD phase transition and its scaling window from Wilson twisted mass fermions

   A.Yu. Kotov🇩🇪 · M.P. Lombardo🇮🇹 · A. Trunin🇷🇺

   We investigate the thermal QCD phase transition and its scaling properties on the lattice. The simulations are performed with $N_f=2+1+1$ Wilson twisted mass fermions at pion masses from physical up to heavy quark regime. We introduce a novel chiral order parameter, which is free from linear mass contributions and turns out to be very useful for the study of scaling behaviour. Our results are compatible with $O(4)$ universal scaling for the physical pion mass and the temperature range $[120:300]$ MeV. Violations to scaling at larger masses and other possible scenarios, including mean field behaviour and $Z(2)$ scaling scenario are also discussed. We provide an estimation for the critical temperature in the chiral limit $T_0$.

   hep-lathep-phhep-thPoS(2022)·2 citations
3. 03*

   Lattice Constraints on the QCD Chiral Phase Transition at Finite Temperature and Baryon Density

   Owe Philipsen🇩🇪

   The thermal restoration of chiral symmetry in QCD is known to proceed by an analytic crossover, which is widely expected to turn into a phase transition with a critical endpoint as the baryon density is increased. In the absence of a genuine solution to the sign problem of lattice QCD, simulations at zero and imaginary baryon chemical potential in a parameter space enlarged by a variable number of quark flavours and quark masses constitute a viable way to constrain the location of a possible non-analytic phase transition and its critical endpoint. In this article I review recent progress towards an understanding of the nature of the transition in the massless limit, and its critical temperature at zero density. Combined with increasingly detailed studies of the physical crossover region, current data bound a possible critical point to ${\mu }_B>3T$.

   hep-latSymmetry(2021)·52 citations
4. 04*

   Scale setting for $\mathcal{N}=1$ SUSY Yang-Mills at large-$N$ through volume-reduced twisted matrix model

   P. Butti🇪🇸 · M. Garcia Perez🇪🇸 · A. Gonzalez-Arroyo🇪🇸 · K. I. Ishikawa🇯🇵 · M. Okawa🇯🇵

   $\mathcal{N}=1$ SUSY Yang-Mills theory is an appealing theoretical framework that has been studied in the literature using different methods, including standard lattice simulations. Among these, the volume-reduced twisted Eguchi-Kawai model, endowed with one adjoint Majorana fermion, could play an important role in studying its large-$N$ limit via the Curci-Veneziano prescription. In this talk, we present our results on the analysis of the scale of the theory, performed via different methods based on purely gluonic observables as well as (quenched) fundamental mesons in the chiral limit. These lattice results will be used as a scale setting for the analysis of the spectrum of the theory.

   hep-lathep-phhep-thPoS(2022)·2 citations
5. 05*

   Dynamics of the $O(4)$ critical point in QCD

   Adrien Florio🇺🇸 · Eduardo Grossi🇺🇸 · Alexander Soloviev🇺🇸 · Derek Teaney🇺🇸

   We perform a real-time simulation of the $O(4)$ critical point of QCD, which lies in the dynamic universality class of Model G. The axial charge and the order parameter ${\varphi }_a=(\sigma ,\vec{\pi })$ exhibit a rich dynamical interplay, which reflects the qualitative differences in the hydrodynamic effective theories above and below $T_c$. From the axial charge correlators on the critical line we extract a dynamical critical exponent of $\zeta =1.47\pm 0.01(\mathrm{stat})$, which is compatible with the theoretical expectation of $\zeta =d/2$ (with $d=3$) when systematic errors are taken into account. At low temperatures, we quantitatively match the $O(4)$ simulations to the superfluid effective theory of soft pions.

   hep-lathep-phhep-thnucl-thPRD(2022)·50 citations
6. 06*

   Transverse momentum broadening in real-time lattice simulations of the glasma

   Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹

   The study of jets in heavy-ion collisions provides important information about the interaction of partons with the medium that they traverse. The seeds of jets are highly energetic partons, which are produced from hard scatterings during the collision event. As such, they are affected by all different stages of the medium's time evolution, including the glasma, which is the pre-equilibrium precursor state of the quark-gluon plasma. Here we report on our numerical lattice simulations of partons traversing the boost-invariant, non-perturbative glasma as created at the early stages of collisions at RHIC and LHC. We find that partons quickly accumulate transverse momentum up to the saturation momentum during the glasma stage. Furthermore, we observe an interesting anisotropy in transverse momentum broadening of partons with larger broadening in the rapidity than in the azimuthal direction. Its origin can be related to correlations among the longitudinal color-electric and color-magnetic flux tubes in the initial state of the glasma. We compare these observations to the semi-analytic results obtained by a weak-field approximation, where we also find such an anisotropy in a parton's transverse momentum broadening.

   ↳ hep-phhep-latnucl-thPoS(2022)·0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.