scholarly journals Heavy light tetraquarks from Lattice QCD

2018 ◽  
Vol 175 ◽  
pp. 05014 ◽  
Author(s):  
Parikshit Junnarkar ◽  
M Padmanath ◽  
Nilmani Mathur
Keyword(s):  
Lattice Qcd ◽  
Lattice Spacing ◽  
Energy Levels ◽  
Clear Indication ◽  
Lattice Calculation ◽  
Charm Quarks ◽  
Preliminary Results ◽  
Scattering State

We present preliminary results from a lattice calculation of tetraquark states in the charm and bottom sector of the type udbb, usbb, udcc and scbb. These calculations are performed on Nf = 2 + 1 + 1 MILC ensembles with lattice spacing of a = 0:12 fm and a = 0:06 fm. A relativistic action with overlap fermions is employed for the light and charm quarks while a non-relativistic action with non-perturbatively improved coefficients is used in the bottom sector. Preliminary results provide a clear indication of presence of energy levels below the relevant thresholds of different tetraquark states in the double bottom sector while a scattering state is observed in the charm sector.

scholarly journals The Upsilon spectrum and the determination of the lattice spacing from lattice QCD including charm quarks in the sea

2012 ◽  
Vol 85 (5) ◽  
Author(s):  
R. J. Dowdall ◽  
B. Colquhoun ◽  
J. O. Daldrop ◽  
C. T. H. Davies ◽  
I. D. Kendall ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Lattice Spacing ◽  
Charm Quarks

scholarly journals D meson semileptonic form factors in Nf = 3 QCD with Möbius domain-wall quarks

2018 ◽  
Vol 175 ◽  
pp. 13007 ◽  
Author(s):  
Takashi Kaneko ◽  
Brian Colquhoun ◽  
Hidenori Fukaya ◽  
Shoji Hashimoto
Keyword(s):  
Domain Wall ◽  
Lattice Qcd ◽  
Momentum Transfer ◽  
Lattice Spacing ◽  
Light Quark ◽  
D Meson ◽  
Form Factors ◽  
Scalar Form ◽  
Charm Quarks ◽  
Quark Masses

e present our calculation of D → π and D → K semileptonic form factors in Nf = 2 + 1 lattice QCD. We simulate three lattice cutoffs a-1 ≃ 2.5, 3.6 and 4.5 GeV with pion masses as low as 230 MeV. The Möbius domain-wall action is employed for both light and charm quarks. We present our results for the vector and scalar form factors and discuss their dependence on the lattice spacing, light quark masses and momentum transfer.

HYPERON-NUCLEON FORCES CALCULATED FROM LATTICE QCD

2009 ◽  
Vol 24 (11) ◽  
pp. 2110-2117
Author(s):  
H. NEMURA ◽  
N. ISHII ◽  
S. AOKI ◽  
T. HATSUDA
Keyword(s):  
Numerical Calculation ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Lattice Spacing ◽  
Finite Lattice ◽  
Temporal Part ◽  
Lattice Volume ◽  
Scattering State ◽  
Spatial Lattice ◽  
Scattering Lengths

We study the hyperon-nucleon (YN) forces by using quenched lattice QCD. The Bethe-Salpeter amplitudes are calculated for the lowest scattering state of the systems so as to obtain the YN potentials. The numerical calculation is twofold: (i) The pΞ0 potentials and scattering lengths are obtained by using lattice QCD with β = 5.7, the lattice spacing of a = 0.1416(9) fm , on the 323 × 32 lattice. Two kinds of ud quark mass are used, corresponding to mπ ≃ 0.37 GeV and 0.51 GeV. The spatial lattice volume is (4.5 fm)3. The scattering lengths obtained from Lüscher's formula show that the pΞ0 interactions are both attractive at 1S0 and 3S1 channels, and the interaction in the 3S1 is more attractive than in the 1S0. These attractive forces become stronger as the u, d quark mass decreases. (ii) The pΛ potentials are calculated. The lattice setup is almost same as the former calculation except for the temporal part. The calculation is performed on 323 × 48 lattice. Two kinds of ud quark mass are used, corresponding to mπ ≃ 0.47 GeV and 0.51 GeV. The lowest scattering energies in the finite lattice volume are calculated.

scholarly journals Nucleon gluon distribution function from 2 + 1 + 1-flavor lattice QCD

2021 ◽  
pp. 2150080
Author(s):  
Zhouyou Fan ◽  
Rui Zhang ◽  
Huey-Wen Lin
Keyword(s):  
Experimental Data ◽  
Lattice Qcd ◽  
Gluon Distribution ◽  
Lattice Spacing ◽  
Distribution Functions ◽  
Coordinate Space ◽  
Lattice Calculation ◽  
Parton Distribution Functions ◽  
Independent Information ◽  
Global Fit

The parton distribution functions (PDFs) provide process-independent information about the quarks and gluons inside hadrons. Although the gluon PDF can be obtained from a global fit to experimental data, it is not constrained well in the large-[Formula: see text] region. Theoretical gluon-PDF studies are much fewer than those of the quark PDFs. In this work, we present the first lattice-QCD results that access the [Formula: see text]-dependence of the gluon unpolarized PDF of the nucleon. The lattice calculation is carried out with nucleon momenta up to 2.16 GeV, lattice spacing [Formula: see text] fm, and with valence pion masses of 310 and 690 MeV. We use reduced Ioffe-time distributions to cancel the renormalization and implement a one-loop perturbative pseudo-PDF gluon matching. We neglect mixing of the gluon operator with the quark singlet sector. Our matrix-element results in coordinate space are consistent with those obtained from the global PDF fits of CT18 NNLO and NNPDF3.1 NNLO. Our fitted gluon PDFs at both pion masses are consistent with global fits in the [Formula: see text] region.

scholarly journals PRESENT CONSTRAINTS ON THE H-DIBARYON AT THE PHYSICAL POINT FROM LATTICE QCD

2011 ◽  
Vol 26 (34) ◽  
pp. 2587-2595 ◽  
Author(s):  
◽  
S. R. BEANE ◽  
E. CHANG ◽  
W. DETMOLD ◽  
B. JOÓ ◽  
...  
Keyword(s):  
Binding Energy ◽  
Lattice Qcd ◽  
Lattice Spacing ◽  
Pion Mass ◽  
Physical Point ◽  
Physical Pion ◽  
Scattering State ◽  
H Dibaryon ◽  
Near Threshold

The current constraints from lattice QCD on the existence of the H-dibaryon are discussed. With only two significant lattice QCD calculations of the H-dibaryon binding energy at approximately the same lattice spacing, the forms of the chiral and continuum extrapolations to the physical point are not determined. In this brief report, we consider the constraints on the H-dibaryon imposed by two simple chiral extrapolations. In both instances, the extrapolation to the physical pion mass allows for a bound H-dibaryon or a near-threshold scattering state. Further lattice QCD calculations are required to clarify this situation.

scholarly journals HVP contributions to the muon (g−2) including QED corrections with twisted-mass fermions

2018 ◽  
Vol 175 ◽  
pp. 06006
Author(s):  
Davide Giusti ◽  
Vittorio Lubicz ◽  
Guido Martinelli ◽  
Francesco Sanfilippo ◽  
Silvano Simula
Keyword(s):  
Lattice Spacing ◽  
Pion Mass ◽  
Charm Quark ◽  
Leading Order ◽  
Lattice Calculation ◽  
Charm Quarks ◽  
Quark Masses ◽  
Mass Collaboration ◽  
Twisted Mass ◽  
The Continuum

We present a lattice calculation of the Hadronic Vacuum Polarization (HVP) contribution of the strange and charm quarks to the anomalous magnetic moment of the muon including leading-order electromagnetic (e.m.) corrections. We employ the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) with Nf = 2+1 + 1 dynamical quarks at three values of the lattice spacing (a ≃ 0.062,0.082,0.089 fm) with pion masses in the range Mπ ≃ 210 - 450 MeV. The strange and charm quark masses are tuned at their physical values. Neglecting discon-nected diagrams and after the extrapolations to the physical pion mass and to the continuum limit we obtain: [see formula in PDF] and [see formula in PDF] for the strange and charm contributions, respectively.!

STUDY OF HYPERON-NUCLEON POTENTIAL FROM LATTICE QCD

2010 ◽  
Vol 19 (12) ◽  
pp. 2442-2447
Author(s):  
H. Nemura ◽  
N. Ishii ◽  
S. Aoki ◽  
T. Hatsuda
Keyword(s):  
Numerical Calculation ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Lattice Spacing ◽  
Nucleon Potential ◽  
Scattering State ◽  
Scattering Lengths

We study pΞ0 and pΛ forces by using quenched lattice QCD. The Bethe-Salpeter amplitude is calculated for the lowest scattering state of the systems. The numerical calculation is twofold: (i) For the pΞ0, the potentials and scattering lengths are obtained by using 323 × 32 lattice with β = 5.7, the lattice spacing of a = 0.1416(9) fm , and two kinds of ud quark mass corresponding to mπ ≃ 0.37 GeV and 0.51 GeV. The present results indicate that the pΞ0 interactions are both attractive at 1S0 and 3S1 channels, and the interaction in the 3S1 is more attractive than in the 1S0. These attractive forces become stronger as the u, d quark mass decreases. (ii) For the pΛ, the potentials are calculated by using the 323 × 48 lattice, and two kinds of ud quark mass corresponding to mπ ≃ 0.47 GeV and 0.51 GeV. The present preliminary result shows that the pΛ interactions are both attractive at 1S0 and 3S1 channels.

scholarly journals Isospin-1/2 Dπ scattering and the lightest $$ {D}_0^{\ast } $$ resonance from lattice QCD

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Luke Gayer ◽  
Nicolas Lang ◽  
Sinéad M. Ryan ◽  
David Tims ◽  
Christopher E. Thomas ◽  
...  
Keyword(s):  
Scattering Amplitudes ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Light Quark ◽  
Energy Levels ◽  
Experimental Result ◽  
Infinite Volume ◽  
Resonance Pole ◽  
Strongly Coupled ◽  
Light Quark Mass

Abstract Isospin-1/2 Dπ scattering amplitudes are computed using lattice QCD, working in a single volume of approximately (3.6 fm)3 and with a light quark mass corresponding to mπ ≈ 239 MeV. The spectrum of the elastic Dπ energy region is computed yielding 20 energy levels. Using the Lüscher finite-volume quantisation condition, these energies are translated into constraints on the infinite-volume scattering amplitudes and hence enable us to map out the energy dependence of elastic Dπ scattering. By analytically continuing a range of scattering amplitudes, a $$ {D}_0^{\ast } $$ D 0 ∗ resonance pole is consistently found strongly coupled to the S-wave Dπ channel, with a mass m ≈ 2200 MeV and a width Γ ≈ 400 MeV. Combined with earlier work investigating the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ , and $$ {D}_0^{\ast } $$ D 0 ∗ with heavier light quarks, similar couplings between each of these scalar states and their relevant meson-meson scattering channels are determined. The mass of the $$ {D}_0^{\ast } $$ D 0 ∗ is consistently found well below that of the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ , in contrast to the currently reported experimental result.

scholarly journals The Leutwyler–Smilga relation on the lattice

2019 ◽  
Vol 35 (01) ◽  
pp. 1950346 ◽  
Author(s):  
Gernot Münster ◽  
Raimar Wulkenhaar
Keyword(s):  
Perturbation Theory ◽  
Quantum Chromodynamics ◽  
Lattice Qcd ◽  
Chiral Perturbation Theory ◽  
Effective Action ◽  
Lattice Spacing ◽  
Chiral Perturbation ◽  
Quark Masses

According to the Leutwyler–Smilga relation, in Quantum Chromodynamics (QCD), the topological susceptibility vanishes linearly with the quark masses. Calculations of the topological susceptibility in the context of lattice QCD, extrapolated to zero quark masses, show a remnant nonzero value as a lattice artefact. Employing the Atiyah–Singer theorem in the framework of Symanzik’s effective action and chiral perturbation theory, we show the validity of the Leutwyler–Smilga relation in lattice QCD with lattice artefacts of order a2 in the lattice spacing a.

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