Thu·Nov 25, 2021Thursday·November 25, 2021

1. 01*

   Renormalization constants of quark bilinear operators in QCD with dynamical up, down, strange and charm quarks

   Matteo Di Carlo🇬🇧 · Martha Constantinou🇺🇸 · Petros Dimopoulos🇮🇹 · Roberto Frezzotti (for the Extended Twisted Mass Collaboration (ETMC))🇮🇹

   We present preliminary results of a calculation of the QCD renormalization constants (RCs) for quark bilinear operators, evaluated non-perturbatively on the lattice in the RI'-MOM scheme. The calculation is performed by using dedicated ensembles with $N_f=4$ degenerate dynamical twisted mass (clover) fermions and the Iwasaki gauge action. A detailed analysis is reported, with emphasis on the control or subtraction of the hadronic contaminations occurring in the lattice estimators of RCs and a check of proper scaling with $a^2$ of the final results. Such a careful study of systematic errors is the counterpart of the high statistical precision reached by current calculations of RCs in the RI'-MOM scheme and is important in order to quote accurate results in phenomenological applications, such as the computation of quark masses.

   hep-latPoS(2021)·1 citation
2. 02*

   Sp(4) gauge theories and beyond the standard model physics

   Biagio Lucini🇬🇧 · Ed Bennett🇬🇧 · Jack Holligan🇬🇧 · Deog Ki Hong🇰🇷 · Ho Hsiao🇹🇼 · Jong-Wan Lee🇰🇷 · C.-J. David Lin🇹🇼 · Michele Mesiti🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇮🇪

   We review numerical results for models with gauge group Sp(2N), discussing the glueball spectrum in the large-N limit, the quenched meson spectrum of Sp(4) with Dirac fermions in the fundamental and in the antisymmetric representation and the Sp(4) gauge model with two dynamical Dirac flavours. We also present preliminary results for the meson spectrum in the Sp(4) gauge theory with two fundamental and three antisymmetric Dirac flavours. The main motivation of our programme is to test whether this latter model is viable as a realisation of Higgs compositeness via the pseudo Nambu Goldstone mechanism and at the same time can provide partial top compositeness. In this respect, we report and briefly discuss preliminary results for the mass of the composite baryon made with two fundamental and one antisymmetric fermion (chimera baryon), whose physical properties are highly constrained if partial top compositeness is at work. Our investigation shows that a fully non-perturbative study of Higgs compositeness and partial top compositeness in Sp(4) is within reach with our current lattice methodology.

   hep-lathep-phhep-thEPJ Web Conf.(2022)·18 citations
3. 03*

   Continuum extrapolation of the gradient-flowed color-magnetic correlator at $1.5T_c$

   Luis Altenkort🇩🇪 · Alexander M. Eller🇩🇪 · Olaf Kaczmarek🇩🇪 · Lukas Mazur🇩🇪 · Guy D. Moore🇩🇪 · Hai-Tao Shu🇩🇪

   In a recently published work we employ gradient flow on the lattice to extract the leading contribution of the heavy quark momentum diffusion coefficient in the heavy quark limit from calculations of a well-known two-point function of color-electric field operators. In this article we want to report the progress of calculating the recently derived color-magnetic correlator that encodes a finite mass correction to this transport coefficient. The calculations we present here are based on the same ensemble of quenched gauge configurations at $1.5T_c$ that we previously used for the color-electric correlator.

   hep-latPoS(2022)·8 citations
4. 04*

   The Chiral Phase Transition in three-flavor QCD from Lattice QCD

   Lorenzo Dini🇩🇪 · Prasad Hegde🇮🇳 · Frithjof Karsch🇩🇪 · Anirban Lahiri🇩🇪 · Christian Schmidt🇩🇪 · Sipaz Sharma🇮🇳

   We analyze the pseudo-critical behavior of three-flavor QCD using highly improved staggered quarks (HISQ) on lattices with temporal extent $N_{\tau }=8$ and for quark masses corresponding to a pseudoscalar Goldstone mass in the range $80\mathrm{MeV}\lesssim m_{\pi }\lesssim 140\mathrm{MeV}$. Our findings are consistent with the occurrence of a second order chiral phase transition at vanishing values of the quark masses. The chiral phase transition temperature at this finite value of the lattice spacing is determined to be $T_c=98_{-6}^{+3}\mathrm{MeV}$. A comparison with a corresponding analysis performed in (2+1)-flavor QCD suggests that the continuum limit extrapolated chiral phase transition temperature in 3-flavor QCD will turn out to be below $90\mathrm{MeV}$.

   hep-latPRD(2022)·71 citations
5. 05*

   Searching for Yang-Lee zeros in O($N$) models

   Felipe Attanasio🇩🇪 · Marc Bauer🇩🇪 · Lukas Kades🇩🇪 · Jan M. Pawlowski🇩🇪

   Near the second order phase transition point, QCD with two flavours of massless quarks can be approximated by an O($4$) model, where a symmetry breaking external field $H$ can be added to play the role of quark mass. The Lee-Yang theorem states that the equation of state in this model has a branch cut along the imaginary $H$ axis for $|Im[H]|>H_c$, where $H_c$ indicates a second order critical point. This point, known as Lee-Yang edge singularity, is of importance to the thermodynamics of the system. We report here on ongoing work to determine the location of $H_c$ via complex Langevin simulations.

   hep-latPoS(2022)·6 citations
6. 06*

   One Flavour QCD as an analogue computer for SUSY

   Michele Della Morte🇩🇰 · Benjamin Jäger🇩🇰 · Francesco Sannino🇩🇰 · J. Tobias Tsang🇩🇰 · Felix P.G. Ziegler🇩🇰

   We numerically study QCD with a single quark flavour on the lattice probing predictions from effective field theories that are equivalent to minimal super-symmetric Yang-Mills theory in the large $N_c$ limit. The hadronic spectrum including excited states is analysed using one gauge coupling and several physical volumes and fermion masses. We use the LapH method and also compute disconnected diagrams. Lattice simulations with an odd number of Wilson fermions give rise to regions of configuration space with a negative fermionic weight entailing a sign problem. We perform a detailed analysis on the spectrum of the Wilson-Dirac operator and report on observed cases of a negative fermion determinant in our ensembles.

   hep-latPoS(2022)·10 citations
7. 07*

   Implementing the three-particle quantization condition for ${\pi }^{+}{\pi }^{+}{K}^{+}$ and related systems

   Tyler D. Blanton🇺🇸 · Fernando Romero-López🇺🇸 · Stephen R. Sharpe🇺🇸

   Recently, the formalism needed to relate the finite-volume spectrum of systems of nondegenerate spinless particles has been derived. In this work we discuss a range of issues that arise when implementing this formalism in practice, provide further theoretical results that can be used to check the implementation, and make available codes for implementing the three-particle quantization condition. Specifically, we discuss the need to modify the upper limit of the cutoff function due to the fact that the left-hand cut in the scattering amplitudes for two nondegenerate particles moves closer to threshold; we describe the decomposition of the three-particle amplitude ${\mathcal{K}}_{\text{df,3}}$ into the matrix basis used in the quantization condition, including both $s$ and $p$ waves, with the latter arising in the amplitude for two nondegenerate particles; we derive the threshold expansion for the lightest three-particle state in the rest frame up to $\mathcal{O}(1/L^5)$; and we calculate the leading-order predictions in chiral perturbation theory for ${\mathcal{K}}_{\text{df,3}}$ in the ${\pi }^{+}{\pi }^{+}{K}^{+}$ and ${\pi }^{+}{K}^{+}{K}^{+}$ systems. We focus mainly on systems with two identical particles plus a third that is different ("2+1" systems). We describe the formalism in full detail, and present numerical explorations in toy models, in particular checking that the results agree with the threshold expansion, and making a prediction for the spectrum of ${\pi }^{+}{\pi }^{+}{K}^{+}$ levels using the two- and three-particle interactions predicted by chiral perturbation theory.

   hep-lathep-phnucl-thJHEP(2022)·42 citations
8. 08*

   Developments in the Tensor Network -- from Statistical Mechanics to Quantum Entanglement

   Kouichi Okunishi🇯🇵 · Tomotoshi Nishino🇯🇵 · Hiroshi Ueda🇯🇵

   Tensor networks (TNs) have become one of the most essential building blocks for various fields of theoretical physics such as condensed matter theory, statistical mechanics, quantum information, and quantum gravity. This review provides a unified description of a series of developments in the TN from the statistical mechanics side. In particular, we begin with the variational principle for the transfer matrix of the 2D Ising model, which naturally leads us to the matrix product state (MPS) and the corner transfer matrix (CTM). We then explain how the CTM can be evolved to such MPS-based approaches as density matrix renormalization group (DMRG) and infinite time-evolved block decimation. We also elucidate that the finite-size DMRG played an intrinsic role for incorporating various quantum information concepts in subsequent developments in the TN. After surveying higher-dimensional generalizations like tensor product states or projected entangled pair states, we describe tensor renormalization groups (TRGs), which are a fusion of TNs and Kadanoff-Wilson type real-space renormalization groups, focusing on their fixed point structures. We then discuss how the difficulty in TRGs for critical systems can be overcome in the tensor network renormalization and the multi-scale entanglement renormalization ansatz.

   ↳ cond-mat.stat-mechhep-lathep-thquant-phJ.Phys.Soc.Jap.(2022)·90 citations
9. 09*

   Mounting Evidence for the Violation of Lepton Flavor Universality

   Andreas Crivellin🇨🇭 · Martin Hoferichter🇨🇭

   The Standard Model (SM) of particle physics was finalized in its current form in the mid-1970s, and has been extensively tested and confirmed ever since, with the discovery of the Higgs boson in 2012 being the last missing piece. While no new particles have been directly discovered at the Large Hadron Collider (LHC) at CERN so far, precision observables sensitive to quantum effects of new particles have accumulated intriguing hints for physics beyond the SM. All these anomalies can be interpreted from the point of view of lepton flavor universality, i.e., as hints that electrons, muons, and tau leptons differ much more than predicted by the SM. These tensions can be explained by postulating the existence of new exotic particles. Future measurements will be able to conclusively test this hypothesis, potentially providing long-awaited evidence how the SM needs to be extended at high energies.

   ↳ hep-phhep-exhep-latnucl-ex+1Science(2021)·47 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.