Bulletin of the American Physical Society
2015 Fall Meeting of the APS Division of Nuclear Physics
Volume 60, Number 13
Wednesday–Saturday, October 28–31, 2015; Santa Fe, New Mexico
Session 1WA: Workshop: Theory and Computation for Neutrinos and Fundamental Symmetries 
Hide Abstracts 
Chair: Joe Carlson, Los Alamos National Laboratory Room: Sweeney Ballroom A 
Wednesday, October 28, 2015 9:00AM  9:30AM 
1WA.00001: Coupledcluster computation of electroweak observables Invited Speaker: Sonia Bacca Recently, coupledcluster computations were extended to electroweak observables in light and mediummass nuclei. In particular, we have reformulated the Lorentz Integral transform method within the coupledcluster formalism [1] to allow the investigation of breakup observables with the continuum properly taken into account. This new method, dubbed LITCC, has permitted abinitio studies of photodisintegration cross sections in stable nuclei (16O, 40Ca) and Coulomb breakup cross sections in unstable nuclei (22O). Next, we aim at studying GamowTeller strengths distribution using this method. I will report on a recent calculation of the total GamowTeller strength in the beta decay of 14C, 22O and 24O [2]. We found that twobody currents lead to a quenching of the Ikeda sum rule and it is interesting to see how the strength is distributed. This will be studied using the LITCC method. Finally, our long term goal is to tackle neutrinonucleus interactions using this coupledcluster theory. Neutrino cross sections and nuclear effects lead to systematic uncertainty in the extraction of oscillation parameters in neutrino experiments. Because detectors include complex nuclei, knowledge of their interactions with neutrinos is required with quantified uncertainties to be used in simulations. The LITCC method is well suited to investigate the chargechanging quasi elastic peak in neutrino scattering. While our goal is to tackle the weak response in 16O, I will show some preliminary results on 4He, in particular regarding the Coulomb sum rule. \\[4pt] [1] S. Bacca, N. Barnea, G. Hagen, G. Orlandini and T. Papenbrock, Phys. Rev. Lett. 111, 122502 (2013).\\[0pt] [2] A. Ekstroem, G.R. Jansen, K.A. Wendt, G. Hagen, T. Papenbrock, S. Bacca, B. Carlsson, D. Gazit, Phys. Rev. Lett. 113, 262504 (2014). [Preview Abstract] 
Wednesday, October 28, 2015 9:30AM  10:00AM 
1WA.00002: Towards More Accurate DoubleBeta Matrix Elements Invited Speaker: Jonathan Engel All the methods currently used to calculate the nuclear matrix elements governing neutrinoless double beta decay omit potentially important correlations. I discuss steps  mostly underway  to improve the most prominent methods: the shell model, the generator coordinate method, the quasiparticle random phase approximation, and the interacting boson model. I focus particularly on the first two. The shell model is beginning to include effective interactions and operators, constructed nonperturbatively from ab initio calculations, that compensate for the parts of Hilbert space it omits. The generator coordinate method is starting to incorporate important nonshape degrees of freedom as coordinates. Both approaches face computational challenges, but stochastic methods will help us to meet them. [Preview Abstract] 
Wednesday, October 28, 2015 10:00AM  10:30AM 
1WA.00003: Electromagnetic and neutralweak response functions of light nuclei Invited Speaker: Alessandro Lovato A major goal of nuclear theory is to understand the strong interaction in nuclei as it manifests itself in terms of two and manybody forces among the nuclear constituents, the protons and neutrons, and the interactions of these constituents with external electroweak probes via one and manybody currents. Using imaginarytime projection technique, quantum Monte Carlo allows for solving the timeindependent Schr\"{o}dinger equation even for Hamiltonians including highly spinisospin dependent two and three body forces. I will present a recent Green’s function Monte Carlo calculation of the quasielastic electroweak response functions in light nuclei, needed to describe electron and neutrino scattering. We found that mesonexchange twobody currents generate excess transverse strength from threshold to the quasielastic to the dip region and beyond. These results challenge the conventional picture of quasi elastic inclusive scattering as being largely dominated by singlenucleon knockout processes. These findings are of particular interest for the interpretation of neutrino oscillation signals. [Preview Abstract] 
Wednesday, October 28, 2015 10:30AM  11:00AM 
1WA.00004: Coffee Break

Wednesday, October 28, 2015 11:00AM  11:30AM 
1WA.00005: Role of nuclear correlations in neutrino interactions with nuclei and nuclear matter. Invited Speaker: Sanjay Reddy Neutrinonuclear interactions play an important role in astrophysics and in terrestrial neutrino experiments. Correlations and interactions between nucleons influence neutrinonucleus crosssections in nuclei for neutrino energies in the range MeVGeV, and neutrino production and propagation in supernovae and neutron stars. To summarize our current understanding ? survey recent calculations neutrinonuclear interaction rates and emphasize the role of nucleonnucleon correlations. I will also discuss some open questions and the need to develop new techniques to extract the nuclear response function using nonperturbative methods that can incorporate both short and longdistance correlations and multiparticle excitations in nuclei and nuclear matter. [Preview Abstract] 
Wednesday, October 28, 2015 11:30AM  12:00PM 
1WA.00006: Constraining neutrinoless doublebeta decay matrix elements Invited Speaker: Javier Menendez Neutrinoless doublebeta decay, if detected, would proof the Majorana nature of neutrinos. The decay lifetime is governed by the absolute neutrino masses and the nuclear matrix elements of the transition. Therefore accurate matrix elements are needed to asses the sensitivity of current and future experiments, and to determine the absolute neutrino masses and hierarchy with neutrinoless doublebeta decay. However, present nuclear matrix element calculations show significant uncertainties. These affect the nuclear structure description of the mother and daughter nuclei, and also the treatment of the transition operator. In this talk I cover recent progress on neutrinoless doublebeta decay nuclear matrix element calculations. On the one hand, I discuss the role of the size of the configuration space and of nuclear structure correlations. By comparing matrix elements obtained with different nuclear structure approaches and interactions, optimal strategies for improving the nuclear structure calculations capturing the most important correlations are identified. On the other hand, I describe first attempts to include twobody currents in the doublebeta decay operator. They can be related to the ``quenching'' of the spinisospin operator empirically found in nuclear structure studies. [Preview Abstract] 
Wednesday, October 28, 2015 12:00PM  12:30PM 
1WA.00007: Status of Lattice QCD calculations of one and twonucleon matrix elements Invited Speaker: André WalkerLoud Lattice QCD calculations of basic hadronic quantities are now often performed with systematic control over the physical pion mass, continuum and infinite volume limits. This progress signals a new era in which lattice QCD will be used to compute basic properties of hadrons, nucleons and light nuclei directly from the Standard Model (SM). In particular, we will be able to use lattice QCD, combined with Effective Field Theory, to make quantitative statements about the interaction of SM matter and potential beyond the SM physics ranging from direct dark matter detection to permanent electric dipole moments. I will briefly review the status and challenges of lattice QCD calculations of select one and twonucleon matrix elements. These calculations are significantly more challenging than the basic quantities computed with all systematics controlled, but substantial progress is being made. [Preview Abstract] 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2022 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700