Present and future prospects for lattice QCD calculations of matrix elements for nEDM

Abstract We perform a lattice study of double parton distributions in the pion, using the relationship between their Mellin moments and pion matrix elements of two local currents. A good statistical signal is obtained for almost all relevant Wick contractions. We investigate correlations in the spatial distribution of two partons in the pion, as well as correlations involving the parton polarisation. The patterns we observe depend significantly on the quark mass. We investigate the assumption that double parton distributions approximately factorise into a convolution of single parton distributions.

Download Full-text

Light-cone sum rules for proton decay

Journal of High Energy Physics ◽

10.1007/jhep05(2021)258 ◽

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.

Download Full-text

Electroweak matrix elements in the two-nucleon sector from lattice QCD

Nuclear Physics A ◽

10.1016/j.nuclphysa.2004.07.007 ◽

2004 ◽

Vol 743 (1-3) ◽

pp. 170-193 ◽

Cited By ~ 52

Author(s):

William Detmold ◽

Martin J. Savage

Keyword(s):

Lattice Qcd ◽

Matrix Elements

Download Full-text

Neutron Electric Dipole Moment on the Lattice

EPJ Web of Conferences ◽

10.1051/epjconf/201817501014 ◽

2018 ◽

Vol 175 ◽

pp. 01014 ◽

Cited By ~ 3

Author(s):

Boram Yoon ◽

Tanmoy Bhattacharya ◽

Rajan Gupta

Keyword(s):

Dipole Moment ◽

Cp Violation ◽

Lattice Qcd ◽

Electric Dipole Moment ◽

Electric Dipole ◽

Beyond The Standard Model ◽

Matrix Elements ◽

The Standard Model ◽

The Status ◽

Good Probe

For the neutron to have an electric dipole moment (EDM), the theory of nature must have T, or equivalently CP, violation. Neutron EDM is a very good probe of novel CP violation in beyond the standard model physics. To leverage the connection between measured neutron EDM and novel mechanism of CP violation, one requires the calculation of matrix elements for CP violating operators, for which lattice QCD provides a first principle method. In this paper, we review the status of recent lattice QCD calculations of the contributions of the QCD Θ-term, the quark EDM term, and the quark chromo-EDM term to the neutron EDM.

Download Full-text

QCD Factorization and PDFs from Lattice QCD Calculation

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194515600411 ◽

2015 ◽

Vol 37 ◽

pp. 1560041 ◽

Cited By ~ 20

Author(s):

Yan-Qing Ma ◽

Jian-Wei Qiu

Keyword(s):

Euclidean Space ◽

Minkowski Space ◽

Lattice Qcd ◽

Correlation Functions ◽

Parton Distribution ◽

Distribution Functions ◽

Matrix Elements ◽

Parton Distribution Functions ◽

Qcd Factorization ◽

The Matrix

In this talk, we review a QCD factorization based approach to extract parton distribution and correlation functions from lattice QCD calculation of single hadron matrix elements of quark-gluon operators. We argue that although the lattice QCD calculations are done in the Euclidean space, the nonperturbative collinear behavior of the matrix elements are the same as that in the Minkowski space, and could be systematically factorized into parton distribution functions with infrared safe matching coefficients. The matching coefficients can be calculated perturbatively by applying the factorization formalism on to asymptotic partonic states.

Download Full-text

Nucleon matrix elements from lattice QCD with all-mode-averaging and a domain-decomposed solver: An exploratory study

Nuclear Physics B ◽

10.1016/j.nuclphysb.2016.11.003 ◽

2017 ◽

Vol 914 ◽

pp. 138-159 ◽

Cited By ~ 16

Author(s):

Georg von Hippel ◽

Thomas D. Rae ◽

Eigo Shintani ◽

Hartmut Wittig

Keyword(s):

Lattice Qcd ◽

Exploratory Study ◽

Matrix Elements

Download Full-text

Muon g – 2 theory: The hadronic part

EPJ Web of Conferences ◽

10.1051/epjconf/201816600022 ◽

2018 ◽

Vol 166 ◽

pp. 00022 ◽

Cited By ~ 70

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.

Download Full-text