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Title: Double- β decay matrix elements from lattice quantum chromodynamics

A lattice quantum chromodynamics (LQCD) calculation of the nuclear matrix element relevant to the $$nn\to ppee\overline{\nu}_e\overline{\nu}_e$$ transition is described in detail, expanding on the results presented in Ref. [1]. This matrix element, which involves two insertions of the weak axial current, is an important input for phenomenological determinations of double-$$\beta$$ decay rates of nuclei. From this exploratory study, performed using unphysical values of the quark masses, the long-distance deuteron-pole contribution to the matrix element is separated from shorter-distance hadronic contributions. This polarizability, which is only accessible in double-weak processes, cannot be constrained from single-$$\beta$$ decay of nuclei, and is found to be smaller than the long-distance contributions in this calculation, but non-negligible. In this work, technical aspects of the LQCD calculations, and of the relevant formalism in the pionless effective field theory, are described. Further calculations of the isotensor axial polarizability, in particular near and at the physical values of the light-quark masses, are required for precise determinations of both two-neutrino and neutrinoless double-$$\beta$$ decay rates in heavy nuclei.
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [4] ;  [5]
  1. City Univ. (CUNY), NY (United States). Dept. of Physics, Graduate School and University Center
  2. Univ. of Washington, Seattle, WA (United States). Inst. for Nuclear Theory, Dept. of Physics
  3. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  4. Univ. of Washington, Seattle, WA (United States). Inst. for Nuclear Theory
  5. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Center for Theoretical Physics
  6. College of William and Mary, Williamsburg, VA (United States). Dept. of Physics
Publication Date:
Report Number(s):
JLAB-THY-17-2500; DOE/OR/-23177-4170; arXiv:1702.02929
Journal ID: ISSN 2470-0010; PRVDAQ; TRN: US1703218
Grant/Contract Number:
PHY11-25915; PHY15-15738; AC02-05CH11231; AC05-00OR22725; SC00-10337; FG02-00ER41132; SC0011090; FG02-04ER41302; SC0010495; AC05-06OR23177; SC0010337
Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 96; Journal Issue: 5; Journal ID: ISSN 2470-0010
American Physical Society (APS)
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21); USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26); USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Orgs:
NPLQCD Collaboration
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1389119