ZEU-NIC

 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); 2019-02-1109:44 [PUBDB-2019-01028] Journal Article Meyer, H. B. Nonperturbative renormalization and $O(a )$-improvement of the nonsinglet vector current with $N_f = 2 + 1$ Wilson fermions and tree-level Symanzik improved gauge action Physical review / D 99(1), 014519 (2019) [10.1103/PhysRevD.99.014519]   In calculating hadronic contributions to precision observables for tests of the Standard Model in lattice QCD, the electromagnetic current plays a central role. Using a Wilson action with $O(a)$ improvement in QCD with $N_ f$ flavors, a counterterm must be added to the vector current in order for its on-shell matrix elements to be $O(a)$ improved. [...] OpenAccess: PDF PDF (PDFA); 2019-01-2910:01 [PUBDB-2019-00846] Report/Journal Article et al Separated Kaon Electroproduction Cross Section and the Kaon Form Factor from 6 GeV JLab Data [JLAB-PHY-18-2645; arXiv:1801.01536] Physical review / C covering nuclear physics C97(2), 025204 (2018) [10.1103/PhysRevC.97.025204]   The H1(e,e′K+)Λ reaction was studied as a function of the Mandelstam variable −t using data from the E01-004 (FPI-2) and E93-018 experiments that were carried out in Hall C at the 6 GeV Jefferson Laboratory. The cross section was fully separated into longitudinal and transverse components, and two interference terms at four-momentum transfers Q2 of 1.00, 1.36, and 2.07GeV2. [...] OpenAccess: PDF PDF (PDFA); 2019-01-1611:53 [PUBDB-2019-00523] Report/Contribution to a conference proceedings Green, J. Systematics in nucleon matrix element calculations [DESY-18-224, arXiv:1812.10574] 36th International Symposium on Lattice Field Theory, LATTICE 2018, East LansingEast Lansing, USA, 22 Jul 2018 - 28 Jul 2018 15 pp. (2018) [10.3204/PUBDB-2019-00523]   The current status of calculations of simple nucleon structure observables is reviewed, with a focus on the axial charge. A major challenge is the combination of an exponentially decaying signal-to-noise ratio and the need for large source-sink separations to eliminate excited-state contributions; efforts to understand and deal with this problem are the focus of the largest section of this review. [...] OpenAccess: PDF PDF (PDFA); 2019-01-1415:08 [PUBDB-2019-00443] Preprint/Report et al Proton and neutron electromagnetic form factors from lattice QCD [arXiv:1812.10311; DESY-18-033]   The electromagnetic form factors of the proton and the neutron are computed within lattice QCD using simulations of maximally twisted mass fermions with masses fixed to their physical values. We analyse two new ensembles of $N_f=2$ and $N_f=2+1+1$ and use several values of the sink-source time separation in the range of 1.0 fm to 1.6 fm to ensure ground state identification. [...] OpenAccess: PDF PDF (PDFA);