scholarly journals Hadronic light-by-light scattering amplitudes from lattice QCD versus dispersive sum rules

2018 ◽  
Vol 98 (7) ◽  
Author(s):  
Antoine Gérardin ◽  
Jeremy Green ◽  
Oleksii Gryniuk ◽  
Georg von Hippel ◽  
Harvey B. Meyer ◽  
...  
Keyword(s):  
Light Scattering ◽  
Scattering Amplitudes ◽  
Lattice Qcd ◽  
Sum Rules

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 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 Light-cone sum rules for proton decay

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ulrich Haisch ◽  
Amando Hala
Keyword(s):  
Lattice Qcd ◽  
Light Cone ◽  
Sum Rules ◽  
State Of The Art ◽  
Form Factors ◽  
Baryon Number ◽  
Proton Decay ◽  
Matrix Elements ◽  
Decay Channels ◽  
Systematic Uncertainties

Abstract We estimate the form factors that parametrise the hadronic matrix elements of proton-to-pion transitions with the help of light-cone sum rules. These form factors are relevant for semi-leptonic proton decay channels induced by baryon-number violating dimension-six operators, as typically studied in the context of grand unified theories. We calculate the form factors in a kinematical regime where the momentum transfer from the proton to the pion is space-like and extrapolate our final results to the regime that is relevant for proton decay. In this way, we obtain estimates for the form factors that show agreement with the state-of-the-art calculations in lattice QCD, if systematic uncertainties are taken into account. Our work is a first step towards calculating more involved proton decay channels where lattice QCD results are not available at present.

scholarly journals DK I = 0, $$ D\overline{K} $$ I = 0, 1 scattering and the $$ {D}_{s0}^{\ast } $$(2317) from lattice QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gavin K. C. Cheung ◽  
◽  
Christopher E. Thomas ◽  
David J. Wilson ◽  
Graham Moir ◽  
...  
Keyword(s):  
Elastic Scattering ◽  
Scattering Amplitudes ◽  
Lattice Qcd ◽  
Finite Volume ◽  
Energy Region ◽  
Light Quark ◽  
Bound State ◽  
Vector Resonance ◽  
Quark Masses ◽  
Partial Waves

Abstract Elastic scattering amplitudes for I = 0 DK and I = 0, 1 $$ D\overline{K} $$ D K ¯ are computed in S, P and D partial waves using lattice QCD with light-quark masses corresponding to mπ = 239 MeV and mπ = 391 MeV. The S-waves contain interesting features including a near-threshold JP = 0+ bound state in I = 0 DK, corresponding to the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ (2317), with an effect that is clearly visible above threshold, and suggestions of a 0+ virtual bound state in I = 0 $$ D\overline{K} $$ D K ¯ . The S-wave I = 1 $$ D\overline{K} $$ D K ¯ amplitude is found to be weakly repulsive. The computed finite-volume spectra also contain a deeply-bound D* vector resonance, but negligibly small P -wave DK interactions are observed in the energy region considered; the P and D-wave $$ D\overline{K} $$ D K ¯ amplitudes are also small. There is some evidence of 1+ and 2+ resonances in I = 0 DK at higher energies.

Light scattering and sum rules of three coexisting phases for quasiternary solutions near the tricritical point

2010 ◽  
Vol 132 (7) ◽  
pp. 074501 ◽  
Author(s):  
Nong Wang ◽  
Xueqin An ◽  
Jinshou Wang ◽  
Xuhong Peng ◽  
Weiguo Shen
Keyword(s):  
Light Scattering ◽  
Sum Rules ◽  
Tricritical Point ◽  
Coexisting Phases

scholarly journals Sum Rules and Bounds on Scattering Amplitudes

1972 ◽  
Vol 6 (10) ◽  
pp. 2943-2952 ◽  
Author(s):  
Robert Savit
Keyword(s):  
Scattering Amplitudes ◽  
Sum Rules

scholarly journals Muon g – 2 theory: The hadronic part

2018 ◽  
Vol 166 ◽  
pp. 00022 ◽  
Author(s):  
Fred Jegerlehner
Keyword(s):  
Light Scattering ◽  
Energy Range ◽  
Lattice Qcd ◽  
Vacuum Polarization ◽  
Recent Progress ◽  
Axial Vector ◽  
Status Report ◽  
Leading Order ◽  
Future Prospects ◽  
Polarization Effects

I present a status report of the hadronic vacuum polarization effects for the muon g–2, to be considered as an update of [1]. The update concerns recent new inclusive R measurements from KEDR in the energy range 1.84 to 3.72 GeV. For the leading order contributions I find [see formula in PDF] based on e+e- data [incl. τ data], [see formula in PDF] (NLO) and [see formula in PDF] (NNLO). Collecting recent progress in the hadronic light-by-light scattering I adopt π0, η, η' [95 ± 12] + axial-vector [8 ± 3] + scalar [-6 ± 1] + π, K loops [-20 ± 5] + quark loops [22 ± 4] + tensor [1 ± 0] + NLO [3 ± 2] which yields [see formula in PDF]. With these updates I find [see formula in PDF] a 4.1 σ deviation. Recent lattice QCD results and future prospects to improve hadronic contributions are discussed.

scholarly journals Light-by-light scattering sum rules constraining meson transition form factors

2012 ◽  
Vol 85 (11) ◽  
Author(s):  
Vladimir Pascalutsa ◽  
Vladyslav Pauk ◽  
Marc Vanderhaeghen
Keyword(s):  
Light Scattering ◽  
Sum Rules ◽  
Form Factors ◽  
Transition Form
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