Tue·Dec 6, 2022Tuesday·December 6, 2022

1. 01*

   Equation of state and Taylor expansions at nonzero isospin chemical potential

   Bastian B. Brandt🇩🇪 · Francesca Cuteri🇩🇪 · Gergely Endrödi🇩🇪

   We compute the equation of state of isospin asymmetric QCD at zero and non-zero temperatures using direct simulations of lattice QCD with three dynamical flavors at physical quark masses. In addition to the pressure and the trace anomaly and their behavior towards the continuum limit, we will particularly discuss the extraction of the speed of sound. Furthermore, we discuss first steps towards the extension of the EoS to small non-zero baryon chemical potentials via Taylor expansion.

   hep-lathep-phnucl-thPoS(2023)·12 citations
2. 02*

   The glueball spectrum with $N_f=4$ light fermions

   Andreas Athenodorou🇨🇾 · Jacob Finkenrath🇨🇾 · Adam Lantos🇨🇾 · Michael Teper🇬🇧

   We investigate the glueball spectrum for $N_f=4$ fermions corresponding to low pion masses of $m_{\pi }\sim 250$MeV. We do so by making use of configurations produced with maximally twisted fermions within the framework of the Extended Twisted Mass Collaboration (ETMC). We extract states that belong to irreducible representations of the octahedral group of rotations $R$ in combination with the quantum numbers of charge conjugation $C$ and parity $P$, i.e. $R^{PC}$. We implement the Generalized Eigenvalue Problem (GEVP) using a basis consisting only of gluonic operators. The purpose of this work is to investigate the effect of light dynamical quarks on the glueball spectrum and how this compares to the statistically more accurate spectrum of the pure gauge theory. We employed large ensembles of the order of $\sim \mathcal{O}(10\mathrm{K})$ configurations for each of three different lattice spacings. Our results demonstrate that in the scalar channel $A_1^{++}$ we obtain an additional, lightest state due to the inclusion of light dynamical quarks while the next two states are consistent with the lightest two states in the pure gauge theory. By contrast the mass of the lightest tensor glueball $J^{PC}=2^{++}$ appears to be insensitive to the inclusion of sea quarks, as is the mass of the lightest pseudoscalar. In addition we perform an investigation of the low lying spectrum of the representation $A_1^{++}$ for $N_f=2+1+1$ twisted mass quarks with low masses and demonstrate that the extra lowest state depends strongly on the pion mass. This suggests that the ground state of the scalar glueball has a large quark content, possibly representing the decay of a glueball to two pions.

   hep-lathep-phPoS(2023)·2 citations
3. 03*

   Adjoint fermions at large-N on the lattice

   P. Butti · M. García Pérez · A. González-Arroyo · K.I. Ishikawa

   Lattice simulations of Yang-Mills theories coupled with $N_f$ flavours of fermions in the adjoint representation provide a way to probe the non-perturbative regime of a plethora of different physical scenarios, such as Supersymmetric Yang-Mills theory to BSM models. We are interested in the large-$N_c$ limit of these theories, for which standard lattice techniques are limited by high-computational costs. Our approach makes use of the well-established twisted volume reduction, which allows one to simulate these theories on a $1^4$ lattice. In this talk, we are going to present a detailed study of the scale setting of these theories, performed with Wilson flow techniques, but endowed with a procedure that allowed us to reduce finite-volume (finite $N_c$) systematic effects. We will apply this procedure to our configurations for $N_f=0,\frac{1}{2},1,2$ and analyze the dependence of the scale on the coupling, the adjoint fermion mass and the number of flavours. For the cases in which enough couplings are available we compared the resulting $\beta$-function with the predictions of perturbation theory, finding very good agreement.

   hep-lathep-thPoS(2023)·1 citation
4. 04*

   Anomalous transport phenomena on the lattice

   Bastian B. Brandt🇩🇪 · Francesca Cuteri🇩🇪 · Gergely Endrődi🇩🇪 · Eduardo Garnacho Velasco🇩🇪 · Gergely Markó🇩🇪

   The interrelation between quantum anomalies and electromagnetic fields leads to a series of non-dissipative transport effects in QCD. In this work we study anomalous transport phenomena with lattice QCD simulations using improved staggered quarks in the presence of a background magnetic field. In particular, we calculate the conductivities both in the free case and in the interacting case, analysing the dependence of these coefficients with several parameters, such as the temperature and the quark mass.

   hep-lathep-phPoS(2023)·10 citations
5. 05*

   QCD mesonic screening masses and restoration of chiral symmetry at high T

   Davide Laudicina🇮🇹 · Mattia Dalla Brida🇨🇭 · Leonardo Giusti🇮🇹 · Tim Harris🇬🇧 · Michele Pepe🇮🇹

   We present a strategy to study QCD non-perturbatively on the lattice at very high temperatures. This strategy exploits a non-perturbative, finite-volume, definition of the strong coupling constant to renormalize the theory. As a first application we compute the flavor non-singlet mesonic screening masses in a wide range of temperature, from $T\sim 1$ GeV up to $\sim 160$ GeV with three flavors in the chiral limit of QCD. Our results show very interesting features of the screening spectrum at very high temperatures. On one hand the mass splitting between the vector and the pseudoscalar screening masses is clearly visible up to the electroweak scale and cannot be explained by the known 1-loop perturbative result. On the other hand the restoration of chiral symmetry manifests itself through the degeneracy of the pseudoscalar and the scalar channels and of the vector and the axial-vector ones. This degeneracy pattern is the one expected by Ward identities associated to the presence of chiral symmetry.

   hep-latPoS(2023)·8 citations
6. 06*

   Particle-dimer approach for the Roper resonance in a finite volume

   Daniel Severt🇩🇪 · Maxim Mai🇺🇸 · Ulf-G. Meißner🇩🇪

   We propose a new finite-volume approach which implements two- and three-body dynamics in a transparent way based on an Effective Field Theory Lagrangian. The formalism utilizes a particle-dimer picture and formulates the quantization conditions based on the self-energy of the decaying particle. The formalism is studied for the case of the Roper resonance, using input from lattice QCD and phenomenology. Finally, finite-volume energy eigenvalues are predicted and compared to existing results of lattice QCD calculations. This crucially provides initial guidance on the necessary level of precision for the finite-volume spectrum.

   hep-lathep-phnucl-thJHEP(2023)·28 citations
7. 07*

   Lattice determination of the topological susceptibility slope ${\chi }^{\prime }$ of $2d{\mathrm{CP}}^{N-1}$ models at large $N$

   Claudio Bonanno🇮🇹

   We compute the topological susceptibility slope ${\chi }^{\prime }$, related to the second moment of the two-point correlator of the topological charge density, of $2d$ ${\mathrm{CP}}^{N-1}$ models for $N=5,11,21$ and $31$ from lattice Monte Carlo simulations. Our strategy consists in performing a double limit: first, we take the continuum limit of ${\chi }^{\prime }$ at fixed smoothing radius in physical units; then, we take the zero-smoothing-radius limit. Since the same strategy can also be applied to $4d$ gauge theories and full QCD, where ${\chi }^{\prime }$ plays an intriguing theoretical and phenomenological role, this work constitutes a step towards the lattice investigation of this quantity in such models.

   hep-lathep-phhep-thPRD(2023)·21 citations
8. 08*

   Error reduction using machine learning on Ising worm simulation

   Jangho Kim🇩🇪 · Wolfgang Unger🇩🇪

   We develop a method to improve on the statistical errors for higher moments using machine learning techniques. We present here results for the dual representation of the Ising model with an external field, derived via the high temperature expansion and simulated by the worm algorithm. We compare two ways of measuring the same set of observables, without and with machine learning: moments of the magnetization and the susceptibility can be improved by using the decision tree method to train the correlations between the higher moments and the second moment obtained from an integrated 2-point function. Those results are compared in small volumes to analytic predictions.

   hep-latPoS(2023)·1 citation
9. 09*

   The hadronic running of the electromagnetic coupling and electroweak mixing angle

   Teseo San José🇩🇪 · Hartmut Wittig🇩🇪 · Marco Cè🇨🇭 · Antoine Gérardin🇫🇷 · Georg von Hippel🇩🇪 · Harvey B. Meyer🇩🇪 · Kohtaroh Miura🇩🇪 · Konstantin Ottnad🇩🇪 · Andreas Risch🇩🇪 · Jonas Wilhelm🇩🇪

   We present results for the hadronic running of the electromagnetic coupling and the weak mixing angle from simulations of lattice QCD with $N_f=2+1$ flavours of $O(a)$-improved Wilson fermions. Using two different discretisations of the vector current, we compute the quark-connected and -disconnected contributions to the hadronic vacuum polarisation (HVP) functions ${\bar{\Pi }}^{\gamma \gamma }$ and ${\bar{\Pi }}^{Z\gamma }$ for spacelike squared momenta $Q^2\le 7$ ${\mathrm{GeV}}^2$. Our results are extrapolated to the physical point using ensembles at four lattice spacings, with pion masses ranging from 130 to 420 MeV. We observe a tension of up to 3.5 standard deviations between our lattice results for $\Delta {\alpha }_{\mathrm{had}}^{(5)}(-Q^2)$ and estimates based on the $\text{R}$-ratio for space-like momenta in the range $Q^2=3-7\mathrm{Ge}{\mathrm{V}}^2$. To obtain an estimate for $\Delta {\alpha }_{\mathrm{had}}^{(5)}(M_Z^2)$, we employ the Euclidean split technique. The implications for comparison with global electroweak fits are assessed.

   hep-lathep-phPoS(2023)·2 citations
10. 10*

    Properties of kaon at non-zero temperature and baryon chemical potential

    G. Bozkır🇹🇷 · A. Türkan🇹🇷 · K. Azizi🇮🇷

    We investigate the spectroscopic properties of the strange particle kaon in the framework of hot and dense QCD. To this end, first, we find the perturbative spectral density, which is connected with both the temperature $T$ and the baryon chemical potential ${\mu }_B$. We include the non-perturbative operators as functions of temperature and baryon chemical potential up to mass dimension five. We perform the calculations in momentum space and use the quark propagator in the hot and dense medium. The numerical results at non-zero temperature and baryon chemical potential demonstrate that the mass of the particle rises considerably by increasing the baryon chemical potential at a fixed temperature (for both the zero and non-zero temperatures) up to approximately ${\mu }_B=0.4$ GeV. After this point, it starts to fall by increasing the baryon chemical potential and it apparently vanishes at ${\mu }_B=(1.03-1.15)$ GeV for finite temperatures: The point of apparent vanishing moves to lower baryon chemical potentials by increasing the temperature. At zero temperature, the mass reaches to roughly a fixed value at higher baryon chemical potentials. On the other hand, the decay constant decreases considerably with respect to baryon chemical potential up to roughly ${\mu }_B=0.4$ GeV, but after this point, it starts to increase in terms of the baryon chemical potential at finite temperatures. At $T=0$, the decay constant reaches to a fixed value at higher chemical potentials, as well. Regarding the dependence on the temperature we observe that, at fixed values of baryon chemical potentials, the mass and decay constant remain roughly unchanged up to $T=50$ MeV and $T=70$ MeV respectively, but after these points, the mass starts to fall and the decay constant starts to rise up to a critical temperature $T=155$ MeV, considerably.

    ↳ hep-phhep-exhep-latEPJA(2023)·12 citations
11. 11*

    Prolegomena to a hybrid classical/Rydberg simulator for hadronization (QuPyth)

    Blake Senseman🇺🇸 · Zane Ozzello🇺🇸 · Kenneth Heitritter🇺🇸 · Yannick Meurice🇺🇸 · Stephen Mrenna🇺🇸

    Programmable neutral-atom arrays provide a promising route to real-time analog simulation of strongly interacting quantum systems. We introduce a two leg Rydberg atom ladder that realizes string dynamics and controllable particle production using experimentally accessible parameters. A mapping between local Rydberg occupations and an emergent electric field yields charge anticharge pairs connected by dynamical strings. Classical simulations enforcing Rydberg blockade constraints identify regimes with suppressed entanglement spreading and tunable particle multiplicities, which are seen to be signatures of confinement and string breaking. Particle multiplicities typically grow monotonically with time and system size and depend sensitively on simulator detuning and interaction scales. These results establish the ladder geometry as a viable near-term analog quantum simulator of string fragmentation, and motivate hybrid workflows in which quantum devices contribute nonperturbative real-time dynamics to event generation.

    ↳ quant-phhep-lathep-phPRD(2026)·9 citations
12. 12*

    Extractions of $|V_{ub}|/|V_{cb}|$ from a combined study of the exclusive $b\to u(c)\ell {\nu }_{\ell }$ decays

    Aritra Biswas🇮🇳 · Soumitra Nandi🇮🇳 · Ipsita Ray🇮🇳

    We have extracted the ratio $|V_{ub}|/|V_{cb}|$ from a combined study of the available inputs on $\bar{B}\to (\pi ,\rho ,\omega ){\ell }^{-}{\bar{\nu }}_{\ell }$ and $\bar{B}({\bar{B}}_s)\to (D^{(\ast )},D_s^{(\ast )}){\ell }^{-}{\bar{\nu }}_{\ell }$ ($\ell =\mu$ or $e$) decays. We have done our analysis with and without the inclusion of the available experimental results on the branching fraction $\mathcal{B}\mathcal{R}({\bar{B}}_s\to K^{+}{\mu }^{-}{\bar{\nu }}_{\mu })$ or the ratio of the rates $\Gamma ({\bar{B}}_s\to K^{+}{\ell }^{-}{\bar{\nu }}_{\ell })/\Gamma ({\bar{B}}_s\to D_s^{+}{\ell }^{-}{\bar{\nu }}_{\ell })$. We have used all the available experimental data on the branching fractions in different $q^2$-bins, the available theory inputs on the form factors from lattice and the light cone sum rule (LCSR) approach; analysed the data in different possible scenarios and presented the results. From a combined analysis of all the $b\to c{\ell }^{-}{\bar{\nu }}_{\ell }$ exclusive decays, we have obtained $|V_{cb}|=(40.5\pm 0.6)\times 10^{-3}$ and from all the $b\to u{\ell }^{-}{\bar{\nu }}_{\ell }$ modes, we obtain $|V_{ub}|=(3.46\pm 0.12)\times 10^{-3}$ which changes to $|V_{ub}|=(3.51\pm 0.13)\times 10^{-3}$ after dropping $\mathcal{B}\mathcal{R}({\bar{B}}_s\to K^{+}{\mu }^{-}{\bar{\nu }}_{\mu })$. We hence report the values of the ratio $|V_{ub}|/|V_{cb}|=0.085\pm 0.003$ and $0.087\pm 0.003$ with and without the input from ${\bar{B}}_s\to K^{+}{\mu }^{-}{\bar{\nu }}_{\mu }$ modes, respectively. We have also predicted the ratio $\Gamma ({\bar{B}}_s\to K^{+}{\ell }^{-}{\bar{\nu }}_{\ell })/\Gamma ({\bar{B}}_s\to D_s^{+}{\ell }^{-}{\bar{\nu }}_{\ell })$ using the fit results. In addition, we provide the predictions of $\mathcal{B}\mathcal{R}({\bar{B}}_s\to K^{+}{\mu }^{-}{\bar{\nu }}_{\mu })$ and $\mathcal{B}\mathcal{R}(\bar{B}\to (\rho ,\omega ){\ell }^{-}{\bar{\nu }}_{\ell })$ in the Standard Model (SM) in small $q^2$-bins.

    ↳ hep-phhep-exhep-latJHEP(2023)·17 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.