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Johannes Heinrich Weber - One of the best experts on this subject based on the ideXlab platform.
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strong Coupling Constant and quark masses from lattice qcd
Progress in Particle and Nuclear Physics, 2020Co-Authors: J Komijani, Peter Petreczky, Johannes Heinrich WeberAbstract:Abstract We review lattice determinations of the charm- and bottom-quark masses and the strong Coupling Constant obtained by different methods. We explain how effective field theory approaches, such as Non-Relativistic QCD (NRQCD), potential Non-Relativistic QCD (pNRQCD), Heavy Quark Effective Theory (HQET) and Heavy Meson rooted All-Staggered Chiral Perturbation Theory (HMrAS χ PT) can help in these determinations. After critically reviewing different lattice results we determine lattice world averages for the strong Coupling Constant, α s ( M Z , N f = 5 ) = 0 . 1180 3 − 0 . 00068 + 0 . 00047 , as well as for the charm-quark mass, m c ( m c , N f = 4 ) = 1 . 2735 ( 35 ) GeV, and the bottom-quark mass, m b ( m b , N f = 5 ) = 4 . 188 ( 10 ) GeV. The above determinations are more precise than the ones obtained by Particle Data Group (PDG).
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strong Coupling Constant and heavy quark masses in 2 1 flavor qcd
Physical Review D, 2019Co-Authors: Peter Petreczky, Johannes Heinrich WeberAbstract:We present a determination of the strong Coupling Constant and heavy quark masses in ($2+1$)-flavor QCD using lattice calculations of the moments of the pseudoscalar quarkonium correlators at several values of the heavy valence quark mass with highly improved staggered quark action. We determine the strong Coupling Constant in the $\overline{\mathrm{MS}}$ scheme at four low-energy scales corresponding to ${m}_{c}$, $1.5{m}_{c}$, $2{m}_{c}$, and $3{m}_{c}$, with ${m}_{c}$ being the charm quark mass. The novel feature of our analysis that up to 11 lattice spacings are used in the continuum extrapolations, with the smallest lattice spacing being 0.025 fm. We obtain ${\mathrm{\ensuremath{\Lambda}}}_{\overline{\mathrm{MS}}}^{{n}_{f}=3}=298\ifmmode\pm\else\textpm\fi{}16\text{ }\text{ }\mathrm{MeV}$, which is equivalent to ${\ensuremath{\alpha}}_{s}(\ensuremath{\mu}={M}_{Z},{n}_{f}=5)=0.1159(12)$. For the charm and bottom quark masses in the $\overline{\mathrm{MS}}$ scheme, we obtain ${m}_{c}(\ensuremath{\mu}={m}_{c},{n}_{f}=4)=1.265(10)\text{ }\text{ }\mathrm{GeV}$ and ${m}_{b}(\ensuremath{\mu}={m}_{b},{n}_{f}=5)=4.188(37)\text{ }\text{ }\mathrm{GeV}$.
Peter Petreczky - One of the best experts on this subject based on the ideXlab platform.
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strong Coupling Constant and quark masses from lattice qcd
Progress in Particle and Nuclear Physics, 2020Co-Authors: J Komijani, Peter Petreczky, Johannes Heinrich WeberAbstract:Abstract We review lattice determinations of the charm- and bottom-quark masses and the strong Coupling Constant obtained by different methods. We explain how effective field theory approaches, such as Non-Relativistic QCD (NRQCD), potential Non-Relativistic QCD (pNRQCD), Heavy Quark Effective Theory (HQET) and Heavy Meson rooted All-Staggered Chiral Perturbation Theory (HMrAS χ PT) can help in these determinations. After critically reviewing different lattice results we determine lattice world averages for the strong Coupling Constant, α s ( M Z , N f = 5 ) = 0 . 1180 3 − 0 . 00068 + 0 . 00047 , as well as for the charm-quark mass, m c ( m c , N f = 4 ) = 1 . 2735 ( 35 ) GeV, and the bottom-quark mass, m b ( m b , N f = 5 ) = 4 . 188 ( 10 ) GeV. The above determinations are more precise than the ones obtained by Particle Data Group (PDG).
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strong Coupling Constant and heavy quark masses in 2 1 flavor qcd
Physical Review D, 2019Co-Authors: Peter Petreczky, Johannes Heinrich WeberAbstract:We present a determination of the strong Coupling Constant and heavy quark masses in ($2+1$)-flavor QCD using lattice calculations of the moments of the pseudoscalar quarkonium correlators at several values of the heavy valence quark mass with highly improved staggered quark action. We determine the strong Coupling Constant in the $\overline{\mathrm{MS}}$ scheme at four low-energy scales corresponding to ${m}_{c}$, $1.5{m}_{c}$, $2{m}_{c}$, and $3{m}_{c}$, with ${m}_{c}$ being the charm quark mass. The novel feature of our analysis that up to 11 lattice spacings are used in the continuum extrapolations, with the smallest lattice spacing being 0.025 fm. We obtain ${\mathrm{\ensuremath{\Lambda}}}_{\overline{\mathrm{MS}}}^{{n}_{f}=3}=298\ifmmode\pm\else\textpm\fi{}16\text{ }\text{ }\mathrm{MeV}$, which is equivalent to ${\ensuremath{\alpha}}_{s}(\ensuremath{\mu}={M}_{Z},{n}_{f}=5)=0.1159(12)$. For the charm and bottom quark masses in the $\overline{\mathrm{MS}}$ scheme, we obtain ${m}_{c}(\ensuremath{\mu}={m}_{c},{n}_{f}=4)=1.265(10)\text{ }\text{ }\mathrm{GeV}$ and ${m}_{b}(\ensuremath{\mu}={m}_{b},{n}_{f}=5)=4.188(37)\text{ }\text{ }\mathrm{GeV}$.
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quark masses and strong Coupling Constant in 2 1 flavor qcd
Physical Review D, 2016Co-Authors: Y Maezawa, Peter PetreczkyAbstract:We present a determination of the strange, charm, and bottom quark masses as well as the strong Coupling Constant in $2+1$ flavor lattice QCD simulations using highly improved staggered quark action. The ratios of the charm quark mass to the strange quark mass and the bottom quark mass to the charm quark mass are obtained from the meson masses calculated on the lattice and found to be ${m}_{c}/{m}_{s}=11.877(91)$ and ${m}_{b}/{m}_{c}=4.528(57)$ in the continuum limit. We also determine the strong Coupling Constant and the charm quark mass using the moments of pseudoscalar charmonium correlators: ${\ensuremath{\alpha}}_{s}(\ensuremath{\mu}={m}_{c})=0.3697(85)$ and ${m}_{c}(\ensuremath{\mu}={m}_{c})=1.267(12)\text{ }\text{ }\mathrm{GeV}$. Our result for ${\ensuremath{\alpha}}_{s}$ corresponds to the determination of the strong Coupling Constant at the lowest energy scale so far and is translated to the value ${\ensuremath{\alpha}}_{s}(\ensuremath{\mu}={M}_{Z},{n}_{f}=5)=0.11622(84)$.
S Aoki - One of the best experts on this subject based on the ideXlab platform.
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strong Coupling Constant from vacuum polarization functions in three flavor lattice qcd with dynamical overlap fermions
Physical Review D, 2010Co-Authors: E Shintani, T Onogi, S Aoki, H Fukaya, Shoji Hashimoto, T Kaneko, N YamadaAbstract:We determine the strong Coupling Constant {alpha}{sub s} from a lattice calculation of vacuum polarization functions (VPF) in three-flavor QCD with dynamical overlap fermions. Fitting lattice data of VPF to the continuum perturbative formula including the operator product expansion, we extract the QCD scale parameter {Lambda}{sub MS}{sup -(3)}. At the Z boson mass scale, we obtain {alpha}{sub s}{sup (5)}(M{sub z}) = 0.1181(3)(+14/-12), where the first error is statistical and the second is our estimate of various systematic uncertainties.
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precise determination of the strong Coupling Constant in n f 2 1 lattice qcd with the schrodinger functional scheme
Journal of High Energy Physics, 2009Co-Authors: S Aoki, K I Ishikawa, N Ishizuka, T Izubuchi, Daisuke Kadoh, K Kanaya, Y Kuramashi, Keiko Murano, Y NamekawaAbstract:We present an evaluation of the running Coupling Constant for Nf = 2+1 QCD. The Schrodinger functional scheme is used as the intermediate scheme to carry out non-perturbative running from the low energy region, where physical scale is introduced, to deep in the high energy perturbative region, where conversion to the scheme is safely performed. Possible systematic errors due to the use of perturbation theory occur only in the conversion from three-flavor to four-flavor running Coupling Constant near the charm mass threshold, where higher order terms beyond 5th order in the β function may not be negligible. For numerical simulations we adopted Iwasaki gauge action and non-perturbatively improved Wilson fermion action with the clover term. Seven renormalization scales are used to cover from low to high energy region and three lattice spacings to take the continuum limit at each scale. A physical scale is introduced from the previous Nf = 2+1 simulation of the CP-PACS/JL-QCD collaboration [1], which covered the up-down quark mass range heavier than mπ ~ 500 MeV. Our final result is = 0.12047(81)(48)(+0−173) and = 239(10)(6)(+0−22) MeV .
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precise determination of the strong Coupling Constant in nf 2 1 lattice qcd with the schr odinger functional scheme
arXiv: High Energy Physics - Lattice, 2009Co-Authors: S Aoki, K I Ishikawa, N Ishizuka, T Izubuchi, Daisuke Kadoh, K Kanaya, Y Kuramashi, Keiko Murano, Y Namekawa, M OkawaAbstract:We present an evaluation of the running Coupling Constant for Nf=2+1 QCD. The Schroedinger functional scheme is used as the intermediate scheme to carry out non-perturbative running from the low energy region, where physical scale is introduced, to deep in the high energy perturbative region, where conversion to the MS-bar scheme is safely performed. Possible systematic errors due to the use of perturbation theory occur only in the conversion from three-flavor to four-flavor running Coupling Constant near the charm mass threshold, where higher order terms beyond 5th order in the $\beta$ function may not be negligible. For numerical simulations we adopted Iwasaki gauge action and non-perturbatively improved Wilson fermion action with the clover term. Seven renormalization scales are used to cover from low to high energy region and three lattice spacings to take the continuum limit at each scale. A physical scale is introduced from the previous Nf=2+1 simulation of the CP-PACS/JL-QCD collaboration, which covered the up-down quark mass range heavier than $m_\pi\sim 500$ MeV.
Vincent Theeuwes - One of the best experts on this subject based on the ideXlab platform.
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fitting the strong Coupling Constant with soft drop thrust
Journal of High Energy Physics, 2019Co-Authors: Simone Marzani, Daniel Reichelt, Steffen Schumann, Gregory Soyez, Vincent TheeuwesAbstract:Soft drop has been shown to reduce hadronisation effects at e+e− colliders for the thrust event shape. In this context, we perform fits of the strong Coupling Constant for the soft-drop thrust distribution at NLO+NLL accuracy to pseudo data generated by the Sherpa event generator. In particular, we focus on the impact of hadronisation corrections, which we estimate both with an analytical model and a Monte-Carlo based one, on the fitted value of αs(mZ). We find that grooming can reduce the size of the shift in the fitted value of αs due to hadronisation. In addition, we also explore the possibility of extending the fitting range down to significantly lower values of (one minus) thrust. Here, soft drop is shown to play a crucial role, allowing us to maintain good fit qualities and stable values of the fitted strong Coupling. The results of these studies show that soft-drop thrust is a promising candidate for fitting αs at e+e− colliders with reduced impact of hadronisation effects.
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fitting the strong Coupling Constant with soft drop thrust
arXiv: High Energy Physics - Phenomenology, 2019Co-Authors: Simone Marzani, Daniel Reichelt, Steffen Schumann, Gregory Soyez, Vincent TheeuwesAbstract:Soft drop has been shown to reduce hadronisation effects at $e^+e^-$ colliders for the thrust event shape. In this context, we perform fits of the strong Coupling Constant for the soft-drop thrust distribution at NLO+NLL accuracy to pseudo data generated by the \textsf{Sherpa}~event generator. In particular, we focus on the impact of hadronisation corrections, which we estimate both with an analytical model and a Monte-Carlo based one, on the fitted value of $\alpha_s(m_Z)$. We find that grooming can reduce the size of the shift in the fitted value of $\alpha_s$ due to hadronisation. In addition, we also explore the possibility of extending the fitting range down to significantly lower values of (one minus) thrust. Here, soft drop is shown to play a crucial role, allowing us to maintain good fit qualities and stable values of the fitted strong Coupling. The results of these studies show that soft-drop thrust is a promising candidate for fitting $\alpha_s$ at $e^+ e^-$ colliders with reduced impact of hadronisation effects.
D Timothy R Jones - One of the best experts on this subject based on the ideXlab platform.
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gauss bonnet Coupling Constant in classically scale invariant gravity
Physical Review D, 2015Co-Authors: Martin B Einhorn, D Timothy R JonesAbstract:We discuss the renormalization of higher-derivative gravity, both without and with matter fields, in terms of two primary Coupling Constants rather than three. A technique for determining the dependence of the Gauss-Bonnet Coupling Constant on the remaining Couplings is explained, and consistency with the local form of the Gauss-Bonnet relation in four dimensions is demonstrated to all orders in perturbation theory. A similar argument is outlined for the Hirzebruch signature and its Coupling. We speculate upon the potential implications of instantons on the associated nonperturbative Coupling Constants.
