# ZEU-NIC

 2019-08-1911:35 [PUBDB-2019-03032] Report/Journal Article et al Conformal perturbation theory confronts lattice results in the vicinity of a critical point [arXiv:1904.12749; DESY-19-073] Physical review / D 100(3), 034512 (2019) [10.1103/PhysRevD.100.034512]   We study the accuracy and predictive power of conformal perturbation theory by a comparison with lattice results in the neighborhood of the finite-temperature deconfinement transition of SU(2) Yang-Mills theory, assuming that the infrared properties of this non-Abelian gauge theory near criticality can be described by the Ising model. The results of this comparison show that conformal perturbation theory yields quantitatively accurate predictions in a broad temperature range [...] OpenAccess: PDF PDF (PDFA); 2019-08-0515:34 [PUBDB-2019-02914] Report/Journal Article et al Frequency-splitting estimators of single-propagator traces [arXiv:1903.10447; DESY-19-046]   Single-propagator traces are the most elementary fermion Wick contractions which occur in numerical lattice QCD, and are usually computed by introducing random-noise estimators to profit from volume averaging. The additional contribution to the variance induced by the random noise is typically orders of magnitude larger than the one due to the gauge field [...] OpenAccess: PDF PDF (PDFA); 2019-08-0111:09 [PUBDB-2019-02880] Journal Article/Report/Contribution to a conference proceedings et al Multi-level integration for meson propagators [DESY-18-186; arXiv:1812.01875] The 36th Annual International Symposium on Lattice Field Theory, LATTICE 2018, Michigan State UniversityMichigan State University, East Lansing, 22 Jul 2018 - 28 Jul 2018Contributions / Info Proceedings of Science / International School for Advanced Studies (LATTICE2018), 028 (2019) [10.22323/1.334.0028]   he computation of many correlation functions in lattice QCD is severely hindered by a signal-to-noise problem. Recent developments in the factorization of both the fermion propagator and determinant pave the way for the implementation of multi-level Monte Carlo integration techniques for lattice QCD. [...] OpenAccess: PDF PDF (PDFA); 2019-07-1515:41 [PUBDB-2019-02720] Report/Journal Article et al Systematic uncertainties in parton distribution functions from lattice QCD simulations at the physical point [arXiv:1902.00587] Physical review / D 99(11), 114504 (2019) [10.1103/PhysRevD.99.114504]   We present a detailed study of the helicity-dependent and helicity-independent collinear parton distribution functions (PDFs) of the nucleon, using the quasi-PDF approach. The lattice QCD computation is performed employing twisted mass fermions with a physical value of the light quark mass [...] OpenAccess: PDF PDF (PDFA); 2019-05-2811:31 [PUBDB-2019-02384] Report/Journal Article et al Lattice QCD study of the H dibaryon using hexaquark and two-baryon interpolators [CERN-TH-2018-098; DESY-18-066; HIM-2018-02; MITP-18-030; TIFR-TH-18-12; arXiv:1805.03966] Physical review / D 99(7), 074505 (2019) [10.1103/PhysRevD.99.074505]   We present a lattice QCD spectroscopy study in the isospin singlet, strangeness $-2$ sectors relevant for the conjectured $H$ dibaryon. We employ both hexaquark and two-baryon interpolating operators to isolate the ground state in the rest frame and in moving frames. [...] OpenAccess: PDF PDF (PDFA); 2019-04-2911:14 [PUBDB-2019-02113] Report/Journal Article et al How perturbative are heavy sea quarks? [DESY-18-134; HU-EP-18-28; WUB-18-03; arXiv:1809.03383] Nuclear physics / B 943, 114612 (2019) [10.1016/j.nuclphysb.2019.114612]   Effects of heavy sea quarks on the low energy physics are described by an effective theory where the expansion parameter is the inverse quark mass, 1/$M$. At leading order in 1/$M$ the dependence of any low energy quantity on $M$ is given in terms of the ratio of $\Lambda$ parameters of the effective and the fundamental theory. [...] Restricted: PDF PDF (PDFA); 2019-04-1610:29 [PUBDB-2019-01956] Report/Journal Article Kühn, S. O(3) nonlinear sigma model in 1 + 1 dimensions with matrix product states [arXiv:1812.00944; DESY-18-213] Physical review / D 99(7), 074501 (2019) [10.1103/PhysRevD.99.074501]   We numerically study the spectral properties, the entanglement and the zero-temperature phase structure at nonvanishing chemical potential of the O(3) nonlinear sigma model. Using matrix product states, a particular kind of one-dimensional tensor network states, we show that we are able to reach the asymptotic scaling regime and to reproduce the analytical predictions for the mass gap at vanishing chemical potential. [...] OpenAccess: PDF PDF (PDFA); 2019-04-0109:48 [PUBDB-2019-01785] Preprint/Report et al Nucleon axial, scalar, and tensor charges using lattice QCD at the physical pion mass [arXiv:1903.06487; DESY-19-044]   We report on lattice QCD calculations of the nucleon isovector axial, scalar, and tensor charges. Our calculations are performed on two 2+1-flavor ensembles generated using a 2-HEX-smeared Wilson-clover action at the physical pion mass and lattice spacings $a\approx$ 0.116 and 0.093 fm. [...] OpenAccess: PDF PDF (PDFA); 2019-03-1415:26 [PUBDB-2019-01546] Preprint/Report et al Conformal field theory and the hot phase of three-dimensional U(1) gauge theory [arXiv:1903.00491; DESY-19-027]   We study the high-temperature phase of compact U(1) gauge theory in 2+1 dimensions, comparing the results of lattice calculations with analytical predictions from the conformal-field-theory description of the low-temperature phase of the bidimensional XY model. We focus on the two-point correlation functions of probe charges and the field-strength operator, finding excellent quantitative agreement with the functional form and the continuously varying critical indices predicted by conformal field theory.. OpenAccess: PDF PDF (PDFA); 2019-02-1913:14 [PUBDB-2019-01169] Report/Journal Article Sommer, R. Large $N$ scaling and factorization in SU($N$) Yang-Mills gauge theory [DESY-18-075; arXiv:1805.11070]   The large $N$ limit of SU($N$) gauge theories is well understood in perturbation theory. Also non-perturbative lattice studies have yielded important positive evidence that t Hoofts predictions are valid. [...] OpenAccess: PDF PDF (PDFA);