scholarly journals Constraints for the semileptonic B→D(*) form factors from lattice QCD simulations of two-point correlation functions

2021 ◽  
Vol 104 (9) ◽  
Author(s):  
G. Martinelli ◽  
S. Simula ◽  
L. Vittorio
Keyword(s):  
Lattice Qcd ◽  
Correlation Functions ◽  
Form Factors ◽  
Point Correlation

scholarly journals Light-by-light forward scattering amplitudes in Lattice QCD

2018 ◽  
Vol 175 ◽  
pp. 06030
Author(s):  
Antoine Gérardin ◽  
Jeremy Green ◽  
Oleksii Gryniuk ◽  
Georg von Hippel ◽  
Harvey B. Meyer ◽  
...  
Keyword(s):  
Scattering Amplitudes ◽  
Lattice Qcd ◽  
Cross Sections ◽  
Correlation Functions ◽  
Sum Rules ◽  
Form Factors ◽  
Forward Scattering ◽  
Meson Pole ◽  
Point Correlation ◽  
Dispersive Approach

We present our preliminary results on the calculation of hadronic light-by-light forward scattering amplitudes using vector four-point correlation functions computed on the lattice. Using a dispersive approach, forward scattering amplitudes can be described by γ*γ* → hadrons fusion cross sections and then compared with phenomenology. We show that only a few states are needed to reproduce our data. In particular, the sum rules considered in this study imply relations between meson–γγ couplings and provide valuable information about individual form factors which are often used to estimate the meson-pole contributions to the hadronic light-by-light contribution to the (g – 2) of the muon.

scholarly journals QCD sum rules analysis of weak decays of doubly heavy baryons: the $$b\rightarrow c$$ processes

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Zhi-Peng Xing ◽  
Zhen-Xing Zhao
Keyword(s):  
Correlation Functions ◽  
Sum Rules ◽  
Form Factors ◽  
Final States ◽  
Qcd Sum Rules ◽  
Leptonic Decays ◽  
Weak Decays ◽  
Heavy Baryons ◽  
Point Correlation ◽  
Comprehensive Study

AbstractA comprehensive study of $$b\rightarrow c$$ b → c weak decays of doubly heavy baryons is presented in this paper. The transition form factors as well as the pole residues of the initial and final states are respectively obtained by investigating the three-point and two-point correlation functions in QCD sum rules. Contributions from up to dimension-6 operators are respectively considered for the two-point and three-point correlation functions. The obtained form factors are then applied to a phenomenological analysis of semi-leptonic decays.

scholarly journals Extraction of bare form factors for Bs →Kℓν decays in nonperturbative HQET

2019 ◽  
Vol 34 (28) ◽  
pp. 1950166
Author(s):  
Felix Bahr ◽  
Debasish Banerjee ◽  
Fabio Bernardoni ◽  
Mateusz Koren ◽  
Hubert Simma ◽  
...  
Keyword(s):  
Excited State ◽  
Correlation Functions ◽  
Form Factors ◽  
Matrix Elements ◽  
Final State ◽  
State Formula ◽  
Euclidean Lattice ◽  
Point Correlation ◽  
B Quark ◽  
Static Form

We discuss the extraction of the ground state [Formula: see text] matrix elements from Euclidean lattice correlation functions. The emphasis is on the elimination of excited state contributions. Two typical gauge-field ensembles with lattice spacings 0.075, 0.05 fm and pion masses 330, 270 MeV are used from the O[Formula: see text]-improved CLS 2-flavor simulations and the final state momentum is [Formula: see text] GeV. The b-quark is treated in HQET including the [Formula: see text] corrections. Fits to two-point and three-point correlation functions and suitable ratios including summed ratios are used, yielding consistent results with precision of around 2% which is not limited by the [Formula: see text] corrections but by the dominating static form factors. Excited state contributions are under reasonable control but are the bottleneck towards precision. We do not yet include a specific investigation of multi-hadron contaminations, a gap in the literature which ought to be filled soon.

J/ψ COUPLINGS TO OPEN CHARM MESONS FROM QCD SUM RULES

2005 ◽  
Vol 14 (04) ◽  
pp. 555-567 ◽  
Author(s):  
R. D. MATHEUS ◽  
F. S. NAVARRA ◽  
M. NIELSEN ◽  
R. RODRIGUES DA SILVA
Keyword(s):  
Correlation Functions ◽  
Constituent Quark ◽  
Sum Rules ◽  
Form Factors ◽  
Constituent Quark Model ◽  
Coupling Constants ◽  
Momentum Dependence ◽  
Charm Mesons ◽  
Qcd Sum Rules ◽  
Point Correlation

We employ QCD sum rules to calculate the J/ψ form factors and coupling constants with charmed mesons, by studying three-point correlation functions. In particular, we consider the J/ψD*D and J/ψDD vertices. We determine the momentum dependence of the form factors for kinematical conditions where J/ψ, D or D* are off-shell. Extrapolating to the pole of each of the form factors obtained, we determine the coupling constants. For both couplings, our results (within the errors) are compatible with estimates based on the constituent quark model.

scholarly journals Nucleon axial coupling from Lattice QCD

2018 ◽  
Vol 175 ◽  
pp. 01008 ◽  
Author(s):  
Chia Cheng Chang ◽  
Amy Nicholson ◽  
Enrico Rinaldi ◽  
Evan Berkowitz ◽  
Nicolas Garron ◽  
...  
Keyword(s):  
Domain Wall ◽  
Lattice Qcd ◽  
Present State ◽  
Correlation Functions ◽  
State Of The Art ◽  
Gradient Flow ◽  
Relative Uncertainty ◽  
Domain Wall Fermions ◽  
Flow Algorithm ◽  
Point Correlation

We present state-of-the-art results from a lattice QCD calculation of the nucleon axial coupling, gA, using Möbius Domain-Wall fermions solved on the dynamical Nf = 2 + 1 + 1 HISQ ensembles after they are smeared using the gradient-flow algorithm. Relevant three-point correlation functions are calculated using a method inspired by the Feynman-Hellmann theorem, and demonstrate significant improvement in signal for fixed stochastic samples. The calculation is performed at five pion masses of mπ ~ {400, 350, 310, 220, 130} MeV, three lattice spacings of a ~ {0.15, 0.12, 0.09} fm, and we do a dedicated volume study with mπL ~ {3.22, 4.29, 5.36}. Control over all relevant sources of systematic uncertainty are demonstrated and quantified. We achieve a preliminary value of gA = 1.285(17), with a relative uncertainty of 1.33%.

scholarly journals The semi-leptonic form factors of $$\Lambda _{b}\rightarrow \Lambda _{c}$$ and $$\Xi _{b}\rightarrow \Xi _{c}$$ in QCD sum rules

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Zhen-Xing Zhao ◽  
Run-Hui Li ◽  
Yue-Long Shen ◽  
Yu-Ji Shi ◽  
Yan-Sheng Yang
Keyword(s):  
Correlation Function ◽  
Lattice Qcd ◽  
Sum Rules ◽  
Form Factors ◽  
Leading Order ◽  
Qcd Sum Rules ◽  
Point Correlation ◽  
Point Correlation Function

AbstractIn this work, the full leading order results of the form factors for $$\Xi _{b}\rightarrow \Xi _{c}$$ Ξ b → Ξ c and $$\Lambda _{b}\rightarrow \Lambda _{c}$$ Λ b → Λ c are obtained in QCD sum rules. Contributions from up to dimension-5 have been considered. For completeness, we also study the two-point correlation function to obtain the pole residues of $$\Xi _{Q}$$ Ξ Q and $$\Lambda _{Q}$$ Λ Q , and higher accuracy is achieved. For the three-point correlation function, since stable Borel regions cannot be found, about $$20\%$$ 20 % uncertainties are introduced for the form factors of $$\Xi _{b}\rightarrow \Xi _{c}$$ Ξ b → Ξ c and $$\Lambda _{b}\rightarrow \Lambda _{c}$$ Λ b → Λ c . Our results for the form factors are consistent with those of the lattice QCD within errors.

scholarly journals THE FREE FIELD REPRESENTATION OF SU(3) CONFORMAL FIELD THEORY

1993 ◽  
Vol 08 (23) ◽  
pp. 4031-4053
Author(s):  
HOVIK D. TOOMASSIAN
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Correlation Functions ◽  
Free Field ◽  
Field Representation ◽  
Conformal Field ◽  
Point Correlation

The structure of the free field representation and some four-point correlation functions of the SU(3) conformal field theory are considered.

scholarly journals From correlation functions to event shapes in QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
D. Chicherin ◽  
J. M. Henn ◽  
E. Sokatchev ◽  
K. Yan
Keyword(s):  
Correlation Function ◽  
Correlation Functions ◽  
Event Shape ◽  
Proof Of Concept ◽  
Yang Mills ◽  
Point Correlation ◽  
Point Correlation Function ◽  
Event Shapes ◽  
A Charge ◽  
Conserved Currents

Abstract We present a method for calculating event shapes in QCD based on correlation functions of conserved currents. The method has been previously applied to the maximally supersymmetric Yang-Mills theory, but we demonstrate that supersymmetry is not essential. As a proof of concept, we consider the simplest example of a charge-charge correlation at one loop (leading order). We compute the correlation function of four electromagnetic currents and explain in detail the steps needed to extract the event shape from it. The result is compared to the standard amplitude calculation. The explicit four-point correlation function may also be of interest for the CFT community.

scholarly journals Towards a self-consistent analysis of the anisotropic galaxy two- and three-point correlation functions on large scales: application to mock galaxy catalogues

2020 ◽  
Author(s):  
Naonori S Sugiyama ◽  
Shun Saito ◽  
Florian Beutler ◽  
Hee-Jong Seo
Keyword(s):  
Correlation Functions ◽  
Hubble Parameter ◽  
Theoretical Models ◽  
Practical Method ◽  
Acoustic Oscillation ◽  
Nonlinear Damping ◽  
Joint Analysis ◽  
Angular Diameter Distance ◽  
Point Correlation ◽  
Parameter Constraints

Abstract We establish a practical method for the joint analysis of anisotropic galaxy two- and three-point correlation functions (2PCF and 3PCF) on the basis of the decomposition formalism of the 3PCF using tri-polar spherical harmonics. We perform such an analysis with MultiDark Patchy mock catalogues to demonstrate and understand the benefit of the anisotropic 3PCF. We focus on scales above 80 h−1 Mpc, and use information from the shape and the baryon acoustic oscillation (BAO) signals of the 2PCF and 3PCF. We also apply density field reconstruction to increase the signal-noise ratio of BAO in the 2PCF measurement, but not in the 3PCF measurement. In particular, we study in detail the constraints on the angular diameter distance and the Hubble parameter. We build a model of the bispectrum or 3PCF that includes the nonlinear damping of the BAO signal in redshift space. We carefully account for various uncertainties in our analysis including theoretical models of the 3PCF, window function corrections, biases in estimated parameters from the fiducial values, the number of mock realizations to estimate the covariance matrix, and bin size. The joint analysis of the 2PCF and 3PCF monopole and quadrupole components shows a $30\%$ and $20\%$ improvement in Hubble parameter constraints before and after reconstruction of the 2PCF measurements, respectively, compared to the 2PCF analysis alone. This study clearly shows that the anisotropic 3PCF increases cosmological information from galaxy surveys and encourages further development of the modeling of the 3PCF on smaller scales than we consider.

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