Date: Thu, 28 Sep 17 00:17:12 GMT Subject: hep-lat daily 3 new + 5 crosses received by eprepget ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ Send any comments regarding submissions directly to submitter. ------------------------------------------------------------------------------ Archives at http://arxiv.org/ To unsubscribe, e-mail To: hep-lat@arXiv.org, Subject: cancel ------------------------------------------------------------------------------ received by eprepget from Mon 25 Sep 17 18:00:00 GMT to Wed 27 Sep 17 18:00:00 GMT ------------------------------------------------------------------------------ \\ arXiv:1709.09264 Date: Tue, 26 Sep 2017 21:22:09 GMT (34kb,D) Title: A linear sigma model for multiflavor gauge theories Authors: Y. Meurice Categories: hep-lat hep-ph hep-th Comments: 6 pages, 2 figures, uses revtex \\ We consider a linear sigma model describing $2N_f^2$ bosons ($\sigma$, ${\bf a_0}$, $\eta '$ and ${\bf \pi}$) as an approximate effective theory for a $SU(3)$ local gauge theory with $N_f$ Dirac fermions in the fundamental representation. The model has a renormalizable $U(N_f)_L\bigotimes U(N_f)_R$ invariant part, which has an approximate $O(2N_f^2)$ symmetry, and two additional terms, one describing the effects of a $SU(N_f)_V$ invariant mass term and the other the effects of the axial anomaly. We calculate the spectrum for arbitrary $N_f$. Using preliminary and published lattice results from the LatKMI collaboration, we found combinations of the masses that vary slowly with the explicit chiral symmetry breaking and $N_f$. This suggests that the anomaly term plays a leading role in the mass spectrum and that simple formulas such as $M_\sigma^2\simeq (2/N_f-C_\sigma)M_{\eta '}^2$ should apply in the chiral limit. Lattice measurements of $M_{\eta '}^2$ and of approximate constants such as $C_\sigma$ could help locating the boundary of the conformal window. We show that our calculation can be adapted for arbitrary representations of the gauge group and in particular to the minimal model with two sextets, where similar patterns are likely to apply. \\ ( https://arxiv.org/abs/1709.09264 , 34kb) ------------------------------------------------------------------------------ \\ arXiv:1709.09424 Date: Wed, 27 Sep 2017 10:00:23 GMT (107kb) Title: Current matrix element in HAL QCD's wave function equivalent potential method Authors: Kai Watanabe and Noriyoshi Ishii Categories: hep-lat Comments: 18 pages, 0 figures \\ We give a formula to calculate a matrix element of a conserved current in the effective quantum mechanics defined by the wave function equivalent potentials proposed by HAL QCD collaboration. As a first step, a non-relativistic field theory with two channel coupling is considered as the original theory, with which a wave function equivalent HAL QCD potential is obtained in a closed analytic form. The external field method is used to derive the formula by demanding that the result should agree with the original theory. With this formula, the matrix element is obtained by sandwiching the effective current operator between the left and the right eigen functions of the effective Hamiltonian associated with the HAL QCD potential. In addition to the naive one-body current, the effective current operator contains an additional two-body term emerging from the degrees of freedom which has been integrated out. \\ ( https://arxiv.org/abs/1709.09424 , 107kb) ------------------------------------------------------------------------------ \\ arXiv:1709.09460 Date: Wed, 27 Sep 2017 11:49:34 GMT (31kb) Title: Fighting topological freezing in the two-dimensional CP$^{N-1}$ model Authors: Martin Hasenbusch Categories: hep-lat Comments: 8 pages, 4 Figures, Talk given at the 35th International Symposium on Lattice Field Theory, 18 - 24 June 2017, Granada, Spain \\ We perform Monte Carlo simulations of the CP$^{N-1}$ model on the square lattice for $N=10$, $21$, and $41$. Our focus is on the severe slowing down related to instantons. To fight this problem we employ open boundary conditions as proposed by L\"uscher and Schaefer for lattice QCD. Furthermore we test the efficiency of parallel tempering of a line defect. Our results for open boundary conditions are consistent with the expectation that topological freezing is avoided, while autocorrelation times are still large. The results obtained with parallel tempering are encouraging. \\ ( https://arxiv.org/abs/1709.09460 , 31kb) %-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%- ------------------------------------------------------------------------------ \\ arXiv:1709.08785 (*cross-listing*) Date: Tue, 26 Sep 2017 02:02:10 GMT (895kb,D) Title: Mixed Precision Solver Scalable to 16000 MPI Processes for Lattice Quantum Chromodynamics Simulations on the Oakforest-PACS System Authors: Taisuke Boku, Ishikawa Ken-Ichi, Yoshinobu Kuramashi and Lawrence Meadows Categories: physics.comp-ph hep-lat Comments: 7 pages, submitted to LHAM'17 "5th International Workshop on Legacy HPC Application Migration" in CANDAR'17 "The Fifth International Symposium on Computing and Networking" and to appear in the proceedings \\ Lattice Quantum Chromodynamics (Lattice QCD) is a quantum field theory on a finite discretized space-time box so as to numerically compute the dynamics of quarks and gluons to explore the nature of subatomic world. Solving the equation of motion of quarks (quark solver) is the most compute-intensive part of the lattice QCD simulations and is one of the legacy HPC applications. We have developed a mixed-precision quark solver for a large Intel Xeon Phi (KNL) system named "Oakforest-PACS", employing the $O(a)$-improved Wilson quarks as the discretized equation of motion. The nested-BiCGSTab algorithm for the solver was implemented and optimized using mixed-precision, communication-computation overlapping with MPI-offloading, SIMD vectorization, and thread stealing techniques. The solver achieved 2.6 PFLOPS in the single-precision part on a $400^3\times 800$ lattice using 16000 MPI processes on 8000 nodes on the system. \\ ( https://arxiv.org/abs/1709.08785 , 895kb) ------------------------------------------------------------------------------ \\ arXiv:1709.08964 (*cross-listing*) Date: Tue, 26 Sep 2017 12:18:04 GMT (204kb,D) Title: Quantum Monte Carlo study of static potential in graphene Authors: N. Yu. Astrakhantsev, V. V. Braguta, M. I. Katsnelson, A. A. Nikolaev and M. V. Ulybyshev Categories: cond-mat.str-el hep-lat Comments: 6 pages, 2 figures \\ In this paper the interaction potential between static charges in suspended graphene is studied within the quantum Monte Carlo approach. We calculated the dielectric permittivity of suspended graphene for the set of temperatures and extrapolated our results to zero temperature. The dielectric permittivity at zero temperature has the following properties. At zero distance $\epsilon=2.24\pm0.02$. Then it rises and at a large distance the dielectric permittivity reaches the plateau $\epsilon\simeq4.20\pm0.66$. The results obtained in this paper allow to draw a conclusion that full account of many-body effects in the dielectric permittivity of suspended graphene gives $\epsilon$ very close to the one-loop results. Contrary to the one-loop result, the two-loop prediction for the dielectric permittivity deviates from our result. So, one can expect large higher order corrections to the two-loop prediction for the dielectric permittivity of suspended graphene. \\ ( https://arxiv.org/abs/1709.08964 , 204kb) ------------------------------------------------------------------------------ \\ arXiv:1709.09023 (*cross-listing*) Date: Fri, 22 Sep 2017 19:26:07 GMT (3610kb,D) Title: XYZ-SU3 Breakings from Laplace Sum Rules at Higher Orders Authors: R. Albuquerque (FAT, UERJ-Rio de Janeiro), S. Narison (LUPM-Montpellier), D. Rabetiarivony and G. Randriamanatrika (iHEPMAD, Antananarivo) Categories: hep-ph hep-ex hep-lat Comments: 54 pages, 13 figures, 22 tables. arXiv admin note: text overlap with arXiv:1609.03351 \\ We present new compact integrated expressions of SU3 breaking corrections to QCD spectral functions of heavy-light molecules and four-quark XYZ-like states at lowest order (LO) of perturbative (PT) QCD and up to d=8 condensates of the OPE. Including N2LO PT corrections in the chiral limit and NLO SU3 PT corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results for the XYZ-like masses and decay constants from QCD spectral sum rules. Systematic errors are estimated from a geometric growth of the higher order PT corrections and from some partially known d=8 non-perturbative contributions. Our optimal results, based on stability criteria, are summarized in Tables 18 to 21 and compared with some LO results in Table 22. In most channels, the SU3 corrections on the meson masses are tiny: < 10% (resp. <3%) for the c (resp. b)-quark channel but can be large for the couplings (< 20%). Within the lowest dimension currents, most of the 0^{++} and 1^{++} states are below the physical thresholds while our predictions cannot discriminate a molecule from a four-quark state. A comparison with the masses of some experimental candidates indicates that the 0^{++} X(4500) might have a large D^*_{s0}D^*_{s0} molecule component while an interpretation of the 0^{++} candidates as four-quark ground states is not supported by our findings. The 1^{++} X(4147) and X(4273) are compatible with the D^*_{s}D_{s}, \bar D^*_{s0}D_{s1} molecules and/or with the axial-vector A_c four-quark ground state. Our results for the 0^{-\pm}, 1^{-\pm} and for different beauty states can be tested in the future data. Finally, we revisit our previous estimates [1] for the D^*_{0}D^*_{0} and D^*_{0}D_{1} and present new results for the D_1D_1. \\ ( https://arxiv.org/abs/1709.09023 , 3610kb) ------------------------------------------------------------------------------ \\ arXiv:1709.09446 (*cross-listing*) Date: Wed, 27 Sep 2017 10:59:41 GMT (121kb) Title: Perturbative width of open rigid-strings Authors: A. S. Bakry, X. Chen, M. Deliyergiyev, A. Galal, and P-M. Zhang Categories: hep-th hep-lat hep-ph Comments: 31 Pages, 2 Figures, 4 Appendices \\ We present perturbative calculation of the width of the energy profile of stiff strings up to two loops in D dimensions. The perturbative expansion of the extrinsic curvature term signifying the rigidity of the string in Polyakov-Kleinert action is taken around the free Nambu-Goto string. The mean-square width of the string field is derived for open strings with Dirichlet boundary condition. \\ ( https://arxiv.org/abs/1709.09446 , 121kb) ------------------------------------------------------------------------------ \\ arXiv:1709.09466 (*cross-listing*) Date: Wed, 27 Sep 2017 12:14:08 GMT (199kb,D) Title: Axion dark matter and the Lattice Authors: Guy D. Moore Categories: hep-ph hep-lat Comments: 18 pages with 9 figures, plenary talk at conference "Lattice 2017" (Granada, Spain) \\ First I will review the QCD theta problem and the Peccei-Quinn solution, with its new particle, the axion. I will review the possibility of the axion as dark matter. If PQ symmetry was restored at some point in the hot early Universe, it should be possible to make a definite prediction for the axion mass if it constitutes the Dark Matter. I will describe progress on one issue needed to make this prediction -- the dynamics of axionic string-wall networks and how they produce axions. Then I will discuss the sensitivity of the calculation to the high temperature QCD topological susceptibility. My emphasis is on what temperature range is important, and what level of precision is needed. \\ ( https://arxiv.org/abs/1709.09466 , 199kb) %%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%% ------------------------------------------------------------------------------ \\ arXiv:1609.08922 (*cross-listing*) replaced with revised version Tue, 26 Sep 2017 14:27:18 GMT (1439kb,D) Title: The CP-odd sector and $\theta$ dynamics in holographic QCD Authors: Daniel Arean, Ioannis Iatrakis, Matti Jarvinen, Elias Kiritsis Categories: hep-ph hep-lat hep-th Comments: 58 pages plus appendices, 19 figures. V2: section 3.1 improved, typos corrected, published version Report-no: CCQCN-2016-151, CCTP-2016-8, MPP-2016-167 Journal-ref: Phys. Rev. D 96, 026001 (2017) DOI: 10.1103/PhysRevD.96.026001 \\ ( https://arxiv.org/abs/1609.08922 , 1439kb) ------------------------------------------------------------------------------ \\ arXiv:1706.01247 replaced with revised version Tue, 26 Sep 2017 12:10:00 GMT (806kb,D) Title: Masses and decay constants of the $D_{s0}^*(2317)$ and $D_{s1}(2460)$ from $N_f=2$ lattice QCD close to the physical point Authors: Gunnar S. Bali, Sara Collins, Antonio Cox and Andreas Sch\"afer Categories: hep-lat hep-ph Comments: Very minor changes, references added, corrected typos, final version \\ ( https://arxiv.org/abs/1706.01247 , 806kb) ------------------------------------------------------------------------------ \\ arXiv:1707.07715 (*cross-listing*) replaced with revised version Tue, 26 Sep 2017 15:26:39 GMT (16kb) Title: Anomalous magnetic moment of the muon, a hybrid approach Authors: C. A. Dominguez, H. Horch, B. J\"ager, N. F. Nasrallah, K. Schilcher, H. Spiesberger, H. Wittig Categories: hep-ph hep-lat Comments: 14 pages, added some clarifying text and two references, removed typos, results unchanged. Version to be published in Phys.Rev.D Report-no: MITP/17-045, HIM-2017-04 \\ ( https://arxiv.org/abs/1707.07715 , 16kb) ------------------------------------------------------------------------------ \\ arXiv:1708.03620 (*cross-listing*) replaced with revised version Tue, 26 Sep 2017 05:42:35 GMT (98kb) Title: Radiative decays of the doubly charmed baryons in chiral perturbation theory Authors: Hao-Song Li, Lu Meng, Zhan-Wei Liu and Shi-Lin Zhu Categories: hep-ph hep-ex hep-lat nucl-th Comments: arXiv admin note: text overlap with arXiv:1707.02765, arXiv:1706.06458 \\ ( https://arxiv.org/abs/1708.03620 , 98kb) ------------------------------------------------------------------------------ \\ arXiv:1707.05665 (*cross-listing*) replaced with revised version Wed, 27 Sep 2017 12:29:48 GMT (71kb) Title: The interface tension in the improved Blume-Capel model Authors: Martin Hasenbusch Categories: cond-mat.stat-mech hep-lat Comments: 32 pages, 5 figures, discussion extended typos corrected Journal-ref: Phys. Rev. E 96, 032803 (2017) DOI: 10.1103/PhysRevE.96.032803 \\ ( https://arxiv.org/abs/1707.05665 , 71kb) ------------------------------------------------------------------------------ \\ arXiv:1708.01216 replaced with revised version Wed, 27 Sep 2017 17:08:21 GMT (1555kb,A) Title: Improved thermodynamics of SU(2) gauge theory Authors: Pietro Giudice, Stefano Piemonte Categories: hep-lat Comments: 33 pages, 26 figures. Source files of 20 figures (format agr of the program xmgrace) included in the submission as "ancillary files" from which raw data can be extracted. In this second version we modified Fig.23 and Fig.24, added two new plots, four references and we modified Sec.4 Report-no: MS-TP-17-07 \\ ( https://arxiv.org/abs/1708.01216 , 1555kb) %%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%--- For subscribe options to combined physics archives, e-mail To: physics@arxiv.org, Subject: subscribe ----------------------------------------------------------------------------- For help on viewing and making submissions, see http://arxiv.org/help/