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Author Penalva, N.; Hernandez, E.; Nieves, J. url  doi
openurl 
  Title (down) New physics and the tau polarization vector in b -> c tau barnutau decays Type Journal Article
  Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 06 Issue 6 Pages 118 - 37pp  
  Keywords Beyond Standard Model; CP violation  
  Abstract For a general H-b -> Hc tau nu <overbar></mml:mover>tau decay we analyze the role of the tau polarization vector P μin the context of lepton flavor universality violation studies. We use a general phenomenological approach that includes, in addition to the Standard Model (SM) contribution, vector, axial, scalar, pseudoscalar and tensor new physics (NP) terms which strength is governed by, complex in general, Wilson coefficients. We show that both in the laboratory frame, where the initial hadron is at rest, and in the center of mass of the two final leptons, a P -></mml:mover> component perpendicular to the plane defined by the three-momenta of the final hadron and the tau lepton is only possible for complex Wilson coefficients, being a clear signal for physics beyond the SM as well as time reversal (or CP-symmetry) violation. We make specific evaluations of the different polarization vector components for the Lambda (b) -> Lambda (c), <mml:mover accent=“true”>B<mml:mo stretchy=“true”><overbar></mml:mover>c -> eta (c), J/psi and <mml:mover accent=“true”>B<mml:mo stretchy=“true”><overbar></mml:mover> -> D-(*) semileptonic decays, and describe NP effects in the complete two-dimensional space associated with the independent kinematic variables on which the polarization vector depends. We find that the detailed study of P μhas great potential to discriminate between different NP scenarios for 0(-) -> 0(-) decays, but also for Lambda (b) -> Lambda (c) transitions. For this latter reaction, we pay special attention to corrections to the SM predictions derived from complex Wilson coefficients contributions.  
  Address [Penalva, Neus; Nieves, Juan] Ctr Mixto CSIC UV, Inst Invest Paterna, Inst Fis Corpuscular, Apartado 22085, Valencia 46071, Spain, Email: Neus.Penalva@ific.uv.es;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1029-8479 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000664505100002 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 4882  
Permanent link to this record
 

 
Author Yao, D.L.; Fernandez-Soler, P.; Guo, F.K.; Nieves, J. url  doi
openurl 
  Title (down) New parametrization of the form factors in (B)over-bar -> Dl(nu)over-bar(l) decays Type Journal Article
  Year 2020 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 101 Issue 3 Pages 034014 - 7pp  
  Keywords  
  Abstract A new model-independent parametrization is proposed for the hadronic form factors in the semileptonic (B) over bar -> Dl (nu) over bar (l) decay. By a combined consideration of the recent experimental and lattice QCD data, we determine precisely the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cb vertical bar = 41.01(75) x 10(-3) and the ratio R-D = BR((B) over bar -> D tau(nu) over bar (tau))/BR((B) over bar -> Dl (nu) over bar (l)) = 0.301(5). The coefficients in this parametrization, related to phase shifts by sumrulelike dispersion relations and hence called phase moments, encode important scattering information of the (B) over bar (D) over bar interactions which are poorly known so far. Thus, we give strong hints about the existence of at least one bound and one virtual (B) over bar (D) over bar S-wave 0(+) states, subject to uncertainties produced by potentially sizable inelastic effects. This formalism is also applicable for any other semileptonic processes induced by the weak b -> c transition.  
  Address [Yao, De-Liang] Hunan Univ, Sch Phys & Elect, Changsha 410082, Hunan, Peoples R China  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000513217400004 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 4277  
Permanent link to this record
 

 
Author Gran, R.; Nieves, J.; Sanchez, F.; Vicente Vacas, M.J. url  doi
openurl 
  Title (down) Neutrino-nucleus quasi-elastic and 2p2h interactions up to 10 GeV Type Journal Article
  Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 88 Issue 11 Pages 113007 - 10pp  
  Keywords  
  Abstract We extend to 10 GeV results from a microscopic calculation of charged-current neutrino-nucleus reactions that do not produce a pion in the final state. For the class of events coming from neutrino interactions with two nucleons producing two holes (2p2h), limiting the calculation to three-momentum transfers less than 1.2 GeV produces a two-dimensional distribution in momentum and energy transfer that is roughly constant as a function of energy. The cross section for 2p2h interactions approximately scales with the number of nucleons for isoscalar nuclei, similar to the quasi-elastic cross section. When limited to momentum transfers below 1.2 GeV, the cross section is 26% of the quasi-elastic cross section at 3 GeV, but 14% if we neglect a Delta(1232) resonance absorption component. The same quantities are 33% and 17% for antineutrinos. For the quasi-elastic interactions, the full nuclear model with long range correlations produces an even larger, but approximately constant distortion of the shape of the four-momentum transfer at all energies above 2 GeV. The 2p2h enhancement and long-range correlation distortions to the cross section for these interactions are significant enough they should be observable in precision experiments to measure neutrino oscillations and neutrino interactions at these energies, but also balance out and produce less total distortion than each effect does individually.  
  Address [Gran, R.] Univ Minnesota, Dept Phys, Duluth, MN 55812 USA  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000328692000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1666  
Permanent link to this record
 

 
Author Hernandez, E.; Nieves, J. url  doi
openurl 
  Title (down) Neutrino-induced one-pion production revisited: The nu(mu)n -> mu(-)n pi(+) channel Type Journal Article
  Year 2017 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 95 Issue 5 Pages 053007 - 18pp  
  Keywords  
  Abstract Understanding single pion production reactions on free nucleons is the first step towards a correct description of these processes in nuclei, which are important for signal and background contributions in current and near future accelerator neutrino oscillation experiments. In this work, we reanalyze our previous studies of neutrino-induced one-pion production on nucleons for outgoing pi N invariant masses below 1.4 GeV. Our motivation is to get a better description of the nu(mu)n -> mu(-)n pi(+) cross section, for which current theoretical models give values significantly below data. This channel is very sensitive to the crossed Delta(1232) contribution and thus, to spin 1/2 components in the Rarita-Schwinger Delta propagator. We show how these spin 1/2 components are nonpropagating and give rise to contact interactions. In this context, we point out that the discrepancy with experiment might be corrected by the addition of appropriate extra contact terms and argue that this procedure will provide a natural solution to the nu(mu)n -> mu(-)n pi(+) puzzle. To keep our model simple, in this work, we propose to change the strength of the spin 1/2 components in the. propagator and use the nu(mu)n -> mu(-)n pi(+) data to constraint its value. With this modification, we now find a good reproduction of the nu(mu)n -> mu(-)n pi(+) cross section without affecting the good results previously obtained for the other channels. We also explore how this change in the. propagator affects our predictions for pion photoproduction and find also a better agreement with experiment than with the previous model.  
  Address [Hernandez, E.] Univ Salamanca, Dept Fis, E-37008 Salamanca, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000399255000001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3055  
Permanent link to this record
 

 
Author Nieves, J.; Sanchez, F.; Ruiz Simo, I.; Vicente Vacas, M.J. url  doi
openurl 
  Title (down) Neutrino energy reconstruction and the shape of the charged current quasielastic-like total cross section Type Journal Article
  Year 2012 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 85 Issue 11 Pages 113008 - 9pp  
  Keywords  
  Abstract We show that because of the multinucleon mechanism effects, the algorithm used to reconstruct the neutrino energy is not adequate when dealing with quasielastic-like events, and a distortion of the total flux-unfolded cross-section shape is produced. This amounts to a redistribution of strength from high to low energies, which gives rise to a sizable excess (deficit) of low (high) energy neutrinos. This distortion of the shape leads to a good description of the MiniBooNE unfolded charged current quasielastic-like cross sections published by A. A. Aguilar-Arevalo et al. [(MiniBooNE Collaboration), Phys. Rev. D 81, 092005 (2010)]. However, these changes in the shape are artifacts of the unfolding process that ignores multinucleon mechanisms.  
  Address [Nieves, J.] Ctr Mixto Univ Valencia CSIC, Inst Fis Corpuscular IFIC, Inst Invest Paterna, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000305560500002 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 1077  
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