|   | 
Details
   web
Records
Author Pinto-Gomez, F.; De Soto, F.; Ferreira, M.N.; Papavassiliou, J.; Rodriguez-Quintero, J.
Title Lattice three-gluon vertex in extended kinematics: Planar degeneracy Type Journal Article
Year 2023 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 838 Issue Pages 137737 - 8pp
Keywords QCD; Three-gluon vertex; Lattice QCD; Schwinger-Dyson equations
Abstract We present novel results for the three-gluon vertex, obtained from an extensive quenched lattice simulation in the Landau gauge. The simulation evaluates the transversely projected vertex, spanned on a special tensorial basis, whose form factors are naturally parametrized in terms of individually Bosesymmetric variables. Quite interestingly, when evaluated in these kinematics, the corresponding form factors depend almost exclusively on a single kinematic variable, formed by the sum of the squares of the three incoming four-momenta, q, r, and p. Thus, all configurations lying on a given plane in the coordinate system (q2, r2, p2) share, to a high degree of accuracy, the same form factors, a property that we denominate planar degeneracy. We have confirmed the validity of this property through an exhaustive study of the set of configurations satisfying the condition q2 = r2, within the range [0, 5 GeV]. This drastic simplification allows for a remarkably compact description of the main bulk of the data, which is particularly suitable for future numerical applications. A semi-perturbative analysis reproduces the lattice findings rather accurately, once the inclusion of a gluon mass has cured all spurious divergences.
Address [Pinto-Gomez, F.; De Soto, F.] Univ Pablo de Olavide, Dpto Sistemas Fis Quim & Nat, Seville 41013, Spain, Email: jose.rodriguez@dfaie.uhu.es
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:000953425400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5503
Permanent link to this record
 

 
Author Ayala, C.; Cvetic, G.; Kogerler, R.
Title Lattice-motivated holomorphic nearly perturbative QCD Type Journal Article
Year 2017 Publication Journal of Physics G Abbreviated Journal J. Phys. G
Volume 44 Issue 7 Pages 075001 - 30pp
Keywords perturbative QCD; lattice QCD; QCD phenomenology; resummation
Abstract Newer lattice results indicate that, in the Landau gauge at low spacelike momenta, the gluon propagator and the ghost dressing function are finite non-zero. This leads to a definition of the QCD running coupling, in a specific scheme, that goes to zero at low spacelike momenta. We construct a running coupling which fulfills these conditions, and at the same time reproduces to a high precision the perturbative behavior at high momenta. The coupling is constructed in such a way that it reflects qualitatively correctly the holomorphic (analytic) behavior of spacelike observables in the complex plane of the squared momenta, as dictated by the general principles of quantum field theories. Further, we require the coupling to reproduce correctly the nonstrange semihadronic decay rate of tau lepton which is the best measured low-momentum QCD observable with small higher-twist effects. Subsequent application of the Borel sum rules to the V + A spectral functions of tau lepton decays, as measured by OPAL Collaboration, determines the values of the gluon condensate and of the V + A six-dimensional condensate, and reproduces the data to a significantly higher precision than the usual (MS) over bar running coupling.
Address [Ayala, Cesar] Univ Valencia, Dept Theoret Phys, E-46100 Valencia, Spain, Email: Gorazd.Cvetic@usm.cl
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0954-3899 ISBN Medium
Area Expedition Conference
Notes WOS:000402509800001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3167
Permanent link to this record
 

 
Author Bertone, V.; Carrasco, N.; Ciuchini, M.; Dimopoulos, P.; Frezzotti, R.; Gimenez, V.; Lubicz, V.; Martinelli, G.; Mescia, F.; Papinutto, M.; Rossi, G.C.; Silvestrini, L.; Simula, S.; Tarantino, C.; Vladikas, A.
Title Kaon mixing beyond the SM from N-f=2 tmQCD and model independent constraints from the UTA Type Journal Article
Year 2013 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 03 Issue 3 Pages 089 - 53pp
Keywords Lattice QCD; Beyond Standard Model
Abstract We present the first unquenched, continuum limit, lattice QCD results for the matrix elements of the operators describing neutral kaon oscillations in extensions of the Standard Model. Owing to the accuracy of our calculation on Delta S = 2 weak Hamiltonian matrix elements, we are able to provide a refined Unitarity Triangle analysis improving the bounds coming from model independent constraints on New Physics. In our non-perturbative computation we use a combination of N-f = 2 maximally twisted sea quarks and Osterwalder-Seiler valence quarks in order to achieve both O(a)-improvement and continuum-like renormalization properties for the relevant four-fermion operators. The calculation of the renormalization constants has been performed non-perturbatively in the RI-MOM scheme. Based on simulations at four values of the lattice spacing and a number of quark masses we have extrapolated/interpolated our results to the continuum limit and physical light/strange quark masses.
Address Univ Freiburg, Inst Phys, D-79104 Freiburg, Germany, Email: valerio.bertone@cern.ch;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000317522400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1438
Permanent link to this record
 

 
Author Carrasco, N.; Ciuchini, M.; Dimopoulos, P.; Frezzotti, R.; Gimenez, V.; Herdoiza, G.; Lubicz, V.; Michael, C.; Picca, E.; Rossi, G.C.; Sanfilippo, F.; Shindler, A.; Silvestrini, L.; Simula, S.; Tarantino, C.
Title B-physics from N-f=2 tmQCD: the Standard Model and beyond Type Journal Article
Year 2014 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 03 Issue 3 Pages 016 - 52pp
Keywords Lattice QCD; B-Physics; Beyond Standard Model; Quark Masses and SM Parameters
Abstract We present a lattice QCD computation of the b-quark mass, the B and B-s decay constants, the B-mixing bag parameters for the full four-fermion operator basis as well as determinations for xi and f(Bq) root B-i((q)) extrapolated to the continuum limit and to the physical pion mass. We used N-f = 2 twisted mass Wilson fermions at four values of the lattice spacing with pion masses ranging from 280 to 500 MeV. Extrapolation in the heavy quark mass from the charm to the bottom quark region has been carried out on ratios of physical quantities computed at nearby quark masses, exploiting the fact that they have an exactly known infinite mass limit. Our results are m(b)(m(b), (MS) over bar) = 4.29(12) GeV, f(Bs) = 228(8) MeV, f(B) = 189(8) MeV and f(Bs)/f(B) = 1.206(24). Moreover with our results for the bag-parameters we find xi = 1.225(31), B-1((s))/B-1((d)) = 1.01(2), f (Bd) root(B) over cap ((d))(1) = 216(10) MeV and integral Bs root(B) over cap ((s))(1) = 262(10) MeV. We also computed the bag parameters for the complete basis of the four-fermion operators which are required in beyond the SM theories. By using these results for the bag parameters we are able to provide a refined Unitarity Triangle analysis in the presence of New Physics, improving the bounds coming from B-(s) -(B) over bar ((s)) mixing.
Address [Carrasco, N.; Gimenez, V.] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Valencia, Spain, Email: nuria.carrasco@uv.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000347824200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2086
Permanent link to this record
 

 
Author Martinez Torres, A.; Oset, E.; Prelovsek, S.; Ramos, A.
Title Reanalysis of lattice QCD spectra leading to the Ds0*(2317) and Ds1*(2460) Type Journal Article
Year 2015 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 05 Issue 5 Pages 153 - 22pp
Keywords Lattice QCD; Phenomenological Models; QCD
Abstract We perform a reanalysis of the energy levels obtained in a recent lattice QCD simulation, from where the existence of bound states of KD and KD* are induced and identified with the narrow D-s0*(2317) and D-s1*(2460) resonances. The reanalysis is done in terms of an auxiliary potential, employing a single-channel basis KD(*()), and a two-channel basis KD(*()), eta D-s(()*()). By means of an extended Luscher method we determine poles of the continuum t-matrix, bound by about 40 MeV with respect to the KD and KD* thresholds, which we identify with the D-s0*(2317) and D-s1*(2460) resonances. Using a sum rule that reformulates Weinberg compositeness condition we can determine that the state D-s0*(2317) contains a KD component in an amount of about 70%, while the state D-s1*(2460) contains a similar amount of KD*. We argue that the present lattice simulation results do not still allow us to determine which are the missing channels in the bound state wave functions and we discuss the necessary information that can lead to answer this question.
Address [Martinez Torres, A.] Univ Sao Paulo, Inst Fis, BR-05389970 Sao Paulo, SP, Brazil, Email: amartine@if.usp.br;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000355346500002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2258
Permanent link to this record