# Los Alamos National Laboratory

# Theoretical Physics Quarterly Progress Reports

# Los Alamos HEP Theory Quarterly Report FY2019-Q2

## Lattice QCD

The Los Alamos Lattice QCD team and their collaborators are carrying out precision studies investigating signatures of new physics at the TeV scale, Novel CP violating operator's contribution to nEDM, elucidating the structure of the nucleon, and neutrino-nucleon interactions. Progress during this quarter on these projects is described below. The team is also actively working on Quantum Information and Computing under the DOE call "Quantum Information Science Enabled Discovery for High Energy Physics".

### Nucleon charges and form-factors

The analysis of isovector and flavor diagonal charges, g_{A}, g_{S} and g_{T}, from the 2+1+1-flavor clover-on-HISQ calculations was completed and results published in three papers in PRD. The analysis of electric, magnetic and axial vector form factors using up to 3-state fits for both the 2+1+1-flavor clover-on-HISQ and 2+1-flavor clover on clover lattice QCD formulations was carried out and manuscripts describing the results are in final stages of preparation. Gupta completed and submitted manuscripts for two plenary review talks at Spin 2018 and co-authored the FLAG 2019 review on nucleon matrix elements. The FLAG report was finalized and submitted for publication in this period.

FLAG Review arXiv:1902.08191

Physical Review D98 (2018) 094512 arXiv:1806.10604

Physical Review D98 (2018) 091501 arXiv:1808.07597

Physical Review D98 (2018) 034503 arXiv:1806.09006

Physical Review D96 (2017) 114503 arXiv:1705.06834

Physical Review D95:5 (2017) 074508

Physical Review D94:5 (2016) 054508

Physical Review D93:11 (2016) 114506

arXiv:1601.01730

Physical Review D92:9 (2015) 094511

Physical Review D89:9 (2014) 094502

Physical Review D85:5 (2012) 054512.

### Matrix elements of novel CP violating operators and nEDM

Calculations of the matrix elements of the quark chromo electric dipole moment operator (cEDM) and its mixing with the pseudoscalar operator, and of the Theta and Weinberg terms are on going. Preliminary results using a variance reduction method developed by us show a factor of ten reduction in errors. Investigations of gradient flow method to deal with the divergent renormalization and mixing problem of the cEDM and Weinberg operators are continuing.

Relevant References:arXiv:1812.06233

arXiv:1712.08557

arXiv:1701.04132

arXiv:1612.08438

arXiv:1601.02264

Physical Review D92:9 (2015) 114026

Physical Review Letters 112:21 (2015) 212002

arXiv:1502.07325

arXiv:1403.2445

arXiv:1212.4918

### Contributions from Disconnected diagrams

The matrix elements of flavor diagonal operators are needed for the analysis of a number of interesting qualities such as the nucleon electric dipole moment, the quark contribution to the nucleon spin, the nucleon sigma term and the strangeness content of the proton, and the interaction of dark matter with nucleons. These matrix elements also get contributions from disconnected diagrams, that are computationally challenging to compute with high precision. Bhattacharya, Gupta and Yoon published two manuscript describing the results (quark contribution to proton spin and neutron EDM) of extensive simulations carried out over the last three years. Developed the calculation of the renormalization factors needed for flavor diagonal operators. With these in hand, the analyses of disconnected contributions on five Wilson-clover ensembles have also been started.

Relevant References:Physical Review D98 (2018) 094512 arXiv:1806.10604

Physical Review D98 (2018) 091501 arXiv:1808.07597

arXiv:1611.01193

### Transverse Momentum Distribution Functions

New simulations, in collaboration with the Regensburg group, are continuing.

Relevant References:

Physical Review D96 (2017) 094508 arXiv:1706.03406

arXiv:1611.01193

arXiv:1601.05717

## Dark Matter and LHC Physics

Graesser and UNM graduate student Jacek Osinski are finishing a manuscript on the impact that non-trivial cosmologies in the early history of the Universe may have on scenarios for topological dark matter. During this time period, Graesser started a new direction of research. He is investigating the constraints magnetars may place on axion and hidden sector monopole models for dark matter.

Relevant References:

Physics Letters B749 (2014) 293

arXiv:1311.2028

Physical Review Letters111 (2013) 121802

JHEP 1302(2013) 046

JHEP 1210(2012) 025

Physics Letters B714 (2012) 267

Physics Review D85 (2012) 054512

arXiv:1107.2666

JHEP 1110(2011) 110

## Michael Graesser: Neutrinoless double beta decay

Graesser continued his research into the neutrinoless double beta decay process nn-> pp ee, extending previous work to next-to-leading order in the chiral expansion. A manuscript is being completed. The neutrinoless double beta decay process (NDBD) is an important probe of any beyond-the-Standard-Model physics that violates lepton number by two units. NDBD provides a critical constraint on Majorana neutrino masses for active neutrinos, interactions of sterile/right-handed neutrinos, and on general classes of multi-TeV physics violating lepton number by two units. An important theoretical program is to use chiral effective theory to systematically describe how such high-energy physics, including Majorana neutrino masses, contribute to the NDBD process.

Relevant References:Journal of High Energy Physics12 (2018) 097 arXiv:1806.02780

Physical Review Letters 120:20 (2018) 202001 arXiv:1802.10097

Journal of High Energy Physics12 (2017) 82 arXiv:1708.09390

Journal of High Energy Physics (2017)99

Physics Letters B769 (2017) 460

## Daniel S. M. Alves

During the past quarter, Daniele Alves has worked on two projects: (1) extension of the neutrino sector to include sterile neutrinos interacting with matter via light mediators; exploration of these models to address short-baseline neutrino anomalies. (2) Extension of entanglement renormalization methods to continuous effective field theories; exploration of numerical implementations via wavelet transform techniques.

Relevant References:

Journal of High Energy Physics 07 (2018) 92 arXiv:1710.03764