20171207 10:32 
[PUBDB201712818]
Report/Journal Article
Yoon, B. ; Engelhardt, M. ; Gupta, R. ; et al
Nucleon transverse momentumdependent parton distributions in lattice QCD: Renormalization patterns and discretization effects
[arXiv:1706.03406; LAUR1724472]
ddc:530
Lattice QCD calculations of transverse momentumdependent parton distribution functions (TMDs) in nucleons are presented, based on the evaluation of nucleon matrix elements of quark bilocal operators with a stapleshaped gauge connection. Both timereversal odd effects, namely, the generalized Sivers and BoerMulders transverse momentum shifts, as well as timereversal even effects, namely, the generalized transversity and one of the generalized wormgear shifts, are studied. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171113 09:42 
[PUBDB201711882]
Preprint/Report
Cè, M. ; Giusti, L. ; Schaefer, S.
Local multiboson factorization of the quark determinant
[HIM201706; CERNTH2017221; DESY17167; arXiv:1711.01592]
We discuss the recently proposed multiboson domaindecomposed factorization of the gaugefield dependence of the fermion determinant in lattice QCD. In particular, we focus on the case of a lattice divided in an arbitrary number of thick time slices. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171113 09:38 
[PUBDB201711880]
Preprint/Report
Husung, N. A. ; Koren, M. ; Krah, P. ; et al
SU(3) Yang Mills theory at small distances and fine lattices
[DESY17176; arXiv:1711.01860]
We investigate the SU(3) Yang Mills theory at small gradient flow time and at short distances. Lattice spacings down to $a=0.015$ fm are simulated with open boundary conditions to allow topology to flow in and out. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171113 09:12 
[PUBDB201711869]
Preprint/Report
Banerjee, D. ; Koren, M. ; Simma, H. ; et al
HQET form factors for $B_s\to K\ell\nu$ decays beyond leading order
[DESY17172; arXiv:1711.01158]
We compute semileptonic $B_s$ decay form factors using Heavy Quark Effective Theory on the lattice. To obtain good control of the $1/m_b$ expansion, one has to take into account not only the leading static order but also the terms arising at $O(1/m_b)$: kinetic, spin and current insertions. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171106 15:49 
[PUBDB201711705]
Report/Journal Article
Alexandrou, C. ; Constantinou, M. ; Hadjiyiannakou, K. ; et al
Gluon momentum fraction of the nucleon from lattice QCD
[arXiv:1611.06901; DESY16223]
ddc:530
We perform a direct calculation of the gluon momentum fraction of the nucleon using maximally twisted mass fermion ensembles with $N_f=2+1+1$ flavors at a pion mass of about $370\,\mathrm{MeV}$ and a lattice spacing of $a\approx 0.082\,\mathrm{fm}$ and with $N_f=2$ flavors at the physical pion mass and a lattice spacing of $a\approx 0.093\,\mathrm{fm}$. In the definition of the gluon operator we employ stout smearing to obtain a statistically significant result for the bare matrix elements. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171102 11:15 
[PUBDB201711647]
Preprint/Report
Chu, D. Y. . ; Jansen, K. ; Knippschild, B. ; et al
HiggsYukawa model on the lattice
[DESY17164; arXiv:1710.09737]
We present results from two projects on lattice calculations for the HiggsYukawa model. First we report progress on the search of firstorder thermal phase transitions in the presence of a dimensionsix operator, with the choices of bare couplings that lead to viable phenomenological predictions. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171102 11:13 
[PUBDB201711646]
Preprint/Report
Giusti, L. ; Cè, M. ; Schaefer, S.
Multiboson block factorization of fermions
[CERNTH2017195; DESY17170; HIM201707; arXiv:1710.09212]
The numerical computations of many quantities of theoretical and phenomenological interest are plagued by statistical errors which increase exponentially with the distance of the sources in the relevant correlators. Notable examples are baryon masses and matrix elements, the hadronic vacuum polarization and the lightbylight scattering contributions to the muon g2, and the form factors of semileptonic B decays. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171102 09:42 
[PUBDB201711641]
Preprint/Report
Vera, M. G. ; Sommer, R.
Large $N$ scaling and factorization in $\mathrm{SU}(N)$ YangMills theory
[DESY17153; arXiv:1710.06057]
We present results for Wilson loops smoothed with the YangMills gradient flow and matched through the scale $t_0$. They provide renormalized and precise operators allowing to test the $1/N^2$ scaling both at finite lattice spacing and in the continuum limit. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171026 15:14 
[PUBDB201711580]
Report/Journal Article
Bruno, M. ; Brida, M. D. ; Fritzsch, P. ; et al
QCD Coupling from a Nonperturbative Determination of the ThreeFlavor Λ Parameter
[CERNTH2017129; DESY17088; WUB1703; arXiv:1706.03821]
ddc:550
We present a lattice determination of the $\Lambda$ parameter in threeflavor QCD and the strong coupling at the Z pole mass. Computing the nonperturbative running of the coupling in the range from $0.2\,$GeV to $70\,$GeV, and using experimental input values for the masses and decay constants of the pion and the kaon, we obtain $\Lambda_{\overline{\rm MS}}^{(3)}=341(12)\,$MeV. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records

20171026 14:20 
[PUBDB201711576]
Report/Journal Article
Alexandrou, C. ; Constantinou, M. ; Hadjiyiannakou, K. ; et al
Nucleon Spin and Momentum Decomposition Using Lattice QCD Simulations
[arXiv:1706.02973]
ddc:550
We determine within lattice QCD the nucleon spin carried by valence and sea quarks and gluons.The calculation is performed using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately reproduce the physical pion mass.We find that the total angular momentum carried by the quarks in the nucleon is $J_{u+d+s}$ = 0.408(61)$_{stat}$(48)$_{syst}$ and the gluon contribution is $J_g$ = 0.133(11)$_{stat}$(14)$_{syst}$, giving a total of $J_N$ = 0.54(6)$_{stat}$(5)$_{syst}$ that is consistent with the spin sum. For the quark intrinsic spin contribution, we obtain $\frac 1{2} \Delta \Sigma _{u+d+s}$ 0.201(17)$_{stat}$(5)$_{syst}$. [...]
OpenAccess: PDF PDF (PDFA); Detailed record  Similar records


