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Author (down) Hernandez, E.; Nieves, J. url  doi
openurl 
  Title 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 (down) Flynn, J.M.; Hernandez, E.; Nieves, J. url  doi
openurl 
  Title Triply heavy baryons and heavy quark spin symmetry Type Journal Article
  Year 2012 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 85 Issue 1 Pages 014012 - 10pp  
  Keywords  
  Abstract We study the semileptonic b -> c decays of the lowest-lying triply heavy baryons made from b and c quarks in the limit m(b), m(c) >> Lambda(QCD) and close to the zero-recoil point. The separate heavy-quark spin symmetries strongly constrain the matrix elements, leading to single form factors for ccb -> ccc, bbc -> ccb, and bbb -> bbc baryon decays. We also study the effects on these systems of using a Y-shaped confinement potential, as suggested by lattice QCD results for the interaction between three static quarks.  
  Address [Flynn, J. M.] Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England  
  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:000298989300007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 874  
Permanent link to this record
 

 
Author (down) Du, M.L.; Penalva, N.; Hernandez, E.; Nieves, J. url  doi
openurl 
  Title New physics effects on Lambda(b) -> Lambda(c)*tau(nu)over-bar(tau) decays Type Journal Article
  Year 2022 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 106 Issue 5 Pages 055039 - 21pp  
  Keywords  
  Abstract We benefit from a recent lattice determination of the full set of vector, axial and tensor form factors for the Lambda(b) -> Lambda(c)* (2595)tau(nu) over bar (tau) and Lambda(c) (2625)tau(nu) over bar (tau) semileptonic decays to study the possible role of these two reactions in lepton flavor universality violation studies. Using an effective theory approach, we analyze different observables that can be accessed through the visible kinematics of the charged particles produced in the tau decay, for which we consider the pi(-)nu(tau), rho(-) nu(tau) and mu(-)(nu) over bar (mu)nu(tau) channels. We compare the results obtained in the Standard Model and other schemes containing new physics (NP) interactions, with either left-handed or right-handed neutrino operators. We find a discriminating power between models similar to the one of the Lambda(b) -> Lambda(c) decay, although somewhat hindered in this case by the larger errors of the Lambda(b) -> Lambda(c)* lattice form factors. Notwithstanding this, the analysis of these reactions is already able to discriminate between some of the NP scenarios and its potentiality will certainly improve when more precise form factors are available.  
  Address [Du, Meng-Lin; Penalva, Neus; Nieves, Juan] Inst Fis Corpuscular Ctr Mixto CSIC UV, Inst Invest Paterna, C Catedrat Jose Beltran 2, E-46980 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 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000870152800009 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5401  
Permanent link to this record
 

 
Author (down) Du, M.L.; Hernandez, E.; Nieves, J. url  doi
openurl 
  Title Is the Lambda(c)(2625)(+) the heavy quark spin symmetry partner of the Lambda(c)(2595)(+) ? Type Journal Article
  Year 2022 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 106 Issue 11 Pages 114020 - 22pp  
  Keywords  
  Abstract We use a O(alpha(s). Lambda(QCD)/m(c)) heavy quark effective theory scheme, where only O(Lambda(QCD)/mb) corrections are neglected, to study the matrix elements of the scalar, pseudoscalar, vector, axial-vector and tensor currents between the Lambda(b) ground state and the odd parity charm Lambda(c)(2595)(+) and Lambda(c)(2625)(+) resonances. We show that in the near-zero recoil regime, the scheme describes reasonably well, taking into account uncertainties, the results for the 24 form factors obtained in lattice QCD (LQCD) just in terms of only four Isgur-Wise (IW) functions. We also find some support for the possibility that the Lambda(c)(2595)(+) and Lambda(c)(2625)(+) resonances might form a heavy quark spin symmetry (HQSS) doublet. However, we argue that the available LQCD description of these two resonances is not accurate enough to disentangle the possible effects of the Sigma(c)pi and Sigma(c)*pi thresholds, located only a few MeV above their position, and that it cannot be ruled out that these states are not HQSS partners. Finally, we study the ratio d Gamma/[Lambda(b) -> Lambda(c,1/2)-*l (v) over bar (l)]/dq(2)/d Gamma/[Lambda(b) -> Lambda(c,3/2)-*l (v) over bar (l)]/dq(2) of the Standard Model differential semileptonic decay widths, with q the four-momentum transferred between the initial and final hadrons. We provide a natural explanation for the existence of large deviations, near the zero recoil, of this ratio from 1=2 (value predicted in the infinite heavy quark mass limit, assuming that the Lambda(c,1/2)- and Lambda(c,3/2)- are the two members of a HQSS doublet) based on S-wave contributions to the Lambda(b) -> Lambda(c,1/2)- decay amplitude driven by a subleading IW function.  
  Address [Du, Meng-Lin; Nieves, Juan] Inst Fis Corpuscular Ctr Mixto CSIC UV, Inst Invest Paterna, Apartado 22085, Valencia 46071, Spain, Email: du.ml@uestc.edu.cn;  
  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:000905088600004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5454  
Permanent link to this record
 

 
Author (down) Alvarez-Ruso, L.; Hernandez, E.; Nieves, J.; Vicente Vacas, M.J. url  doi
openurl 
  Title Watson's theorem and the N Delta(1232) axial transition Type Journal Article
  Year 2016 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 93 Issue 1 Pages 014016 - 16pp  
  Keywords  
  Abstract We present a new determination of the N Delta axial form factors from neutrino induced pion production data. For this purpose, the model of Hernandez et al. [Phys. Rev. D 76, 033005 (2007)] is improved by partially restoring unitarity. This is accomplished by imposing Watson's theorem on the dominant vector and axial multipoles. As a consequence, a larger C-5(A) (0), in good agreement with the prediction from the off-diagonal Goldberger-Treiman relation, is now obtained.  
  Address [Alvarez-Ruso, L.; Nieves, J.] Ctr Mixto CSIC Univ Valencia, 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:000368324700003 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 2521  
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