20190819 11:35 
[PUBDB201903032]
Report/Journal Article
Caselle, M. ; Magnoli, N. ; Nada, A. ; et al
Conformal perturbation theory confronts lattice results in the vicinity of a critical point
[arXiv:1904.12749; DESY19073]
We study the accuracy and predictive power of conformal perturbation theory by a comparison with lattice results in the neighborhood of the finitetemperature deconfinement transition of SU(2) YangMills theory, assuming that the infrared properties of this nonAbelian 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 [...]
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20190805 15:34 
[PUBDB201902914]
Report/Journal Article
Giusti, L. ; Harris, T. ; Nada, A. ; et al
Frequencysplitting estimators of singlepropagator traces
[arXiv:1903.10447; DESY19046]
Singlepropagator traces are the most elementary fermion Wick contractions which occur in numerical lattice QCD, and are usually computed by introducing randomnoise 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 [...]
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20190801 11:09 
[PUBDB201902880]
Journal Article/Report/Contribution to a conference proceedings
Giusti, L. ; Harris, T. ; Nada, A. ; et al
Multilevel integration for meson propagators
[DESY18186; arXiv:1812.01875]
he computation of many correlation functions in lattice QCD is severely hindered by a signaltonoise problem. Recent developments in the factorization of both the fermion propagator and determinant pave the way for the implementation of multilevel Monte Carlo integration techniques for lattice QCD. [...]
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20190715 15:41 
[PUBDB201902720]
Report/Journal Article
Alexandrou, C. ; Cichy, K. ; Constantinou, M. ; et al
Systematic uncertainties in parton distribution functions from lattice QCD simulations at the physical point
[arXiv:1902.00587]
We present a detailed study of the helicitydependent and helicityindependent collinear parton distribution functions (PDFs) of the nucleon, using the quasiPDF approach. The lattice QCD computation is performed employing twisted mass fermions with a physical value of the light quark mass [...]
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20190528 11:31 
[PUBDB201902384]
Report/Journal Article
Francis, A. ; Green, J. R. ; Junnarkar, P. M. ; et al
Lattice QCD study of the H dibaryon using hexaquark and twobaryon interpolators
[CERNTH2018098; DESY18066; HIM201802; MITP18030; TIFRTH1812; arXiv:1805.03966]
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 twobaryon interpolating operators to isolate the ground state in the rest frame and in moving frames. [...]
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20190429 11:14 
[PUBDB201902113]
Report/Journal Article
Athenodorou, A. ; Finkenrath, J. ; Knechtli, F. ; et al
How perturbative are heavy sea quarks?
[DESY18134; HUEP1828; WUB1803; arXiv:1809.03383]
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. [...]
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20190416 10:29 
[PUBDB201901956]
Report/Journal Article
Bruckmann, F. ; Jansen, K. ; Kühn, S.
O(3) nonlinear sigma model in 1 + 1 dimensions with matrix product states
[arXiv:1812.00944; DESY18213]
We numerically study the spectral properties, the entanglement and the zerotemperature phase structure at nonvanishing chemical potential of the O(3) nonlinear sigma model. Using matrix product states, a particular kind of onedimensional 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. [...]
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20190401 09:48 
[PUBDB201901785]
Preprint/Report
Hasan, N. ; Green, J. ; Meinel, S. ; et al
Nucleon axial, scalar, and tensor charges using lattice QCD at the physical pion mass
[arXiv:1903.06487; DESY19044]
We report on lattice QCD calculations of the nucleon isovector axial, scalar, and tensor charges. Our calculations are performed on two 2+1flavor ensembles generated using a 2HEXsmeared Wilsonclover action at the physical pion mass and lattice spacings $a\approx$ 0.116 and 0.093 fm. [...]
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20190314 15:26 
[PUBDB201901546]
Preprint/Report
Caselle, M. ; Nada, A. ; Panero, M. ; et al
Conformal field theory and the hot phase of threedimensional U(1) gauge theory
[arXiv:1903.00491; DESY19027]
We study the hightemperature phase of compact U(1) gauge theory in 2+1 dimensions, comparing the results of lattice calculations with analytical predictions from the conformalfieldtheory description of the lowtemperature phase of the bidimensional XY model. We focus on the twopoint correlation functions of probe charges and the fieldstrength operator, finding excellent quantitative agreement with the functional form and the continuously varying critical indices predicted by conformal field theory..
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20190219 13:14 
[PUBDB201901169]
Report/Journal Article
Garcia Vera, M. F. ; Sommer, R.
Large $N$ scaling and factorization in SU($N$) YangMills gauge theory
[DESY18075; arXiv:1805.11070]
The large $N$ limit of SU($N$) gauge theories is well understood in perturbation theory. Also nonperturbative lattice studies have yielded important positive evidence that t Hoofts predictions are valid. [...]
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