Tue·Oct 12, 2021Tuesday·October 12, 2021

1. 01*

   Interglueball potential in lattice SU(N) gauge theories

   Nodoka Yamanaka🇯🇵 · Atsushi Nakamura🇯🇵 · Masayuki Wakayama🇯🇵

   The dynamics of the glueballs is important in the context of the experimental search as well as for understanding the non-Abelian gauge theory. The glueballs of the dark $SU(N_c)$ Yang-Mills theory are also good candidates of dark matter. In this proceedings contribution, we report on the result of the lattice calculation of the interglueball potential of the Yang-Mills theory with the color numbers $N_c=2,3,4$, with a detailed inspection of the systematics due to the discretization.

   hep-lathep-phnucl-thPoS(2022)·13 citations
2. 02*

   Determination of the light, strange and charm quark masses using twisted mass fermions

   C. Alexandrou🇨🇾 · S. Bacchio🇨🇾 · G. Bergner🇩🇪 · M. Constantinou🇺🇸 · M. Di Carlo🇬🇧 · P. Dimopoulos🇮🇹 · J. Finkenrath🇨🇾 · E. Fiorenza🇩🇪 · R. Frezzotti🇮🇹 · M. Garofalo🇩🇪 · K. Hadjiyiannakou🇨🇾 · B. Kostrzewa🇩🇪 and 14 other authors

   We present results for the light, strange and charm quark masses using $N_f=2+1+1$ twisted mass fermion ensembles at three values of the lattice spacing, including two ensembles simulated with the physical value of the pion mass. The analysis is done both in the meson and baryon sectors. The difference in the mean values found in the two sectors is included as part of the systematic error. The presentation is based on the work of Ref. [1], where more details can be found.

   hep-lathep-phPoS(2022)·1 citation
3. 03*

   Anderson Metal-to-Critical Transition in QCD

   Andrei Alexandru🇺🇸 · Ivan Horváth🇨🇿

   A picture of thermal QCD phase change based on the analogy with metal-to-insulator transition of Anderson type was proposed in the past. In this picture, a low-$T$ thermal state is akin to a metal with deeply infrared (IR) Dirac modes abundant and extended, while a high-$T$ state is akin to an insulator with IR modes depleted and localized below a mobility edge ${\lambda }_{\text{A}}>0$. Here we argue that, while ${\lambda }_{\text{A}}$ exists in QCD, a high-$T$ state is not an insulator in such an analogy. Rather, it is a critical state arising due to a new singular mobility edge at ${\lambda }_{\text{I}R}=0$. This new mobility edge appears upon the transition into the recently proposed IR phase. As a key part of such a metal-to-critical scenario, we present evidence using pure-glue QCD that deeply infrared Dirac modes in the IR phase extend to arbitrarily long distances. This is consistent with our previous suggestion that the IR phase supports scale invariance in the infrared. We discuss the role of Anderson-like aspects in this thermal regime and emphasize that the combination of gauge field topology and disorder plays a key role in shaping its IR physics. Our conclusions are conveyed by the structure of Dirac spectral non-analyticities.

   hep-latcond-mat.dis-nnhep-thnucl-thPLB(2022)·21 citations
4. 04*

   $S$ parameter from a prototype composite-Higgs model

   Yigal Shamir🇮🇱 · Maarten Golterman🇺🇸 · William I. Jay🇺🇸 · Ethan T. Neil🇺🇸 · Benjamin Svetitsky🇮🇱

   We have calculated the low-energy constant $L_{10}$ in a prototype composite Higgs model with dynamical fermions in two different representations of the gauge group. The resulting contribution of the new strong sector to the $S$ parameter is consistent with current bounds on the vacuum misalignment parameter. We end with a brief discussion of future directions.

   hep-lathep-phPoS(2022)·9 citations
5. 05*

   A new method for a lattice calculation of ${\eta }_c\to 2\gamma$

   Yu Meng🇨🇳

   We propose a direct method to calculate the decay width of a hadron decaying to two photons, which is conventionally obtained by an extrapolation for various off-shell form factors. The new method provides an simple way to examine the finite-volune effects. As an example, we apply the method to ${\eta }_c\to 2\gamma$. Using three $N_f=2$ twisted-mass gauge ensembles with different lattice spacings, we obtain the final decay width ${\Gamma }_{{\eta }_c\gamma \gamma }=6.57(15{)}_{\text{stat}}(8{)}_{\text{syst}}$ keV, where the systematic error accounts for the fine-tuning of the charm quark mass. This method can also be applied for other processes which involve the leptonic or radiative particles in the final states.

   hep-lathep-exhep-phPoS(2022)·2 citations
6. 06*

   Excitations of isolated static charges in q=2 Abelian Higgs theory

   Kazue Matsuyama🇺🇸

   In this report, I discuss lattice Monte Carlo evidence of excitations of isolated static charges in q=2 Abelian Higgs theory. The localized excitations are excited states of the interacting fields surrounding the static charges.

   hep-latcond-mat.supr-conPoS(2022)·0 citations
7. 07*

   Global symmetry breaking in gauge theories: the case of multiflavor scalar chromodynamics

   Claudio Bonati🇮🇹 · Andrea Pelissetto🇮🇹 · Ettore Vicari🇮🇹

   Universal features of continuous phase transitions can be investigated by studying the ${\varphi }^4$ field theory with the corresponding global symmetry breaking pattern. When gauge symmetries are present, the same technique is usually applied to a gauge-invariant order parameter field, as in the Pisarski-Wilczek analysis of the QCD chiral phase transition. Gauge fields are thus assumed to be irrelevant in the effective critical model, a fact that is however far from trivial. We will investigate the validity of this approach using three-dimensional scalar lattice models with non-abelian global and local symmetries, for which critical exponents and scaling functions can be numerically determined with high accuracy.

   hep-latcond-mat.stat-mechPoS(2022)·1 citation
8. 08*

   Lattice Simulation of Multi-Stream Inflation

   Tingqi Cai🇨🇳 · Jie Jiang🇨🇳 · Yi Wang🇨🇳

   We present the first lattice simulation to investigate the nature of multi-stream inflation. The simulation confirms the physical picture of multi-stream inflation, and with new findings in parameter space and field behaviors. Our simulation shows that gradient energy plays a significant role in multi-stream inflation. For a double field potential with a shifted Gaussian barrier, bifurcation probability is controlled by the shift distance with an error function relation. The bubbles created by bifurcation tend to be more spherical as bifurcation probability decreases. Also, the bifurcation is more likely to introduce oscillations of field values inside the bubbles than outside.

   ↳ astro-ph.COhep-lathep-thJCAP(2022)·5 citations
9. 09*

   Nonperturbative two-pion exchange contributions to the nucleon-nucleon interaction in covariant baryon chiral perturbation theory

   Chun-Xuan Wang🇨🇳 · Jun-Xu Lu🇨🇳 · Yang Xiao🇨🇳 · Li-Sheng Geng🇨🇳

   We calculate the nonperturbative two-pion exchange (TPE) contributions to the $NN$ interaction in covariant baryon chiral perturbation theory. We study how the nonperturbative resummation affects the $NN$ phase shifts for partial waves with $J\ge 3$ and $L\le 6$. No significant differences are observed between the nonperturbative phase shifts and perturbative ones for most partial waves except for ${}^3{D}_3$, for which the nonperturbative resummation greatly improves the description of the phase shifts. However, a significant cutoff dependence is found for this partial wave and a reasonable description of the phase shifts can only be obtained with a particular cutoff. Furthermore, we compare the so-obtained nonperturbative phase shifts with those obtained in the heavy baryon chiral perturbation theory. We show that the contributions from relativistic nonperturbative TPE are more moderate than those from the nonrelativistic TPE obtained in the dimensional regularization scheme. A proper convergence pattern is observed for most of the partial waves studied except for ${}^3{F}_3$, ${}^3{F}_4$, and ${}^3{H}_6$, for which the subleading TPE contributions are a bit strong. We find that for $H$ and $I$ partial waves, the OPE alone can already describe the phase shifts reasonably well.

   ↳ nucl-thhep-exhep-lathep-ph+1PRC(2022)·14 citations
10. 10*

    Chiral extrapolation of hadronic vacuum polarization

    Gilberto Colangelo🇨🇭 · Martin Hoferichter🇨🇭 · Bastian Kubis🇩🇪 · Malwin Niehus🇩🇪 · Jacobo Ruiz de Elvira🇨🇭

    We study the pion-mass dependence of the two-pion channel in the hadronic-vacuum-polarization (HVP) contribution to the anomalous magnetic moment of the muon $a_{\mu }^{\text{HVP}}$, by using an Omnès representation for the pion vector form factor with the phase shift derived from the inverse-amplitude method (IAM). Our results constrain the dominant isospin-$1$ part of the isospin-symmetric light-quark contribution, and should thus allow one to better control the chiral extrapolation of $a_{\mu }^{\text{HVP}}$, required for lattice-QCD calculations performed at larger-than-physical pion masses. In particular, the comparison of the one- and two-loop IAM allows us to estimate the associated systematic uncertainties and show that these are under good control.

    ↳ hep-phhep-latnucl-thPLB(2022)·41 citations
11. 11*

    Complex, Lorentzian, and Euclidean simplicial quantum gravity: numerical methods and physical prospects

    Ding Jia🇨🇦

    Evaluating gravitational path integrals in the Lorentzian has been a long-standing challenge due to the numerical sign problem. We show that this challenge can be overcome in simplicial quantum gravity. By deforming the integration contour into the complex, the sign fluctuations can be suppressed, for instance using the holomorphic gradient flow algorithm. Working through simple models, we show that this algorithm enables efficient Monte Carlo simulations for Lorentzian simplicial quantum gravity. In order to allow complex deformations of the integration contour, we provide a manifestly holomorphic formula for Lorentzian simplicial gravity. This leads to a complex version of simplicial gravity that generalizes the Euclidean and Lorentzian cases. Outside the context of numerical computation, complex simplicial gravity is also relevant to studies of singularity resolving processes with complex semi-classical solutions. Along the way, we prove a complex version of the Gauss-Bonnet theorem, which may be of independent interest.

    ↳ gr-qchep-lathep-thClass.Quant.Grav.(2022)·28 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.