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Author Hernandez, E.; Nieves, J.; Valverde, M.; Vicente Vacas, M.J.
Title N-Delta(1232) axial form factors from weak pion production Type Journal Article
Year 2010 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume (down) 81 Issue 8 Pages 085046 - 5pp
Keywords
Abstract The N Delta axial form factors are determined from neutrino induced pion production ANL and BNL data by using a theoretical model that accounts both for background mechanisms and deuteron effects. We find violations of the off-diagonal Goldberger-Treiman relation at the level of 2 sigma which might have an impact in background calculations for T2K and MiniBooNE low energy neutrino oscillation precision experiments.
Address [Hernandez, E.] Univ Salamanca, Dept Fis Fundamental, 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 1550-7998 ISBN Medium
Area Expedition Conference
Notes ISI:000277205000163 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 462
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Author Albertus, C.; Hernandez, E.; Nieves, J.
Title Exclusive c -> s, d Semileptonic Decays of Spin-1/2 and Spin-3/2 cb Baryons Type Journal Article
Year 2014 Publication Few-Body Systems Abbreviated Journal Few-Body Syst.
Volume (down) 55 Issue 8-10 Pages 767-771
Keywords
Abstract We present results for exclusive semileptonic decay widths of ground state spin-1/2 and spin-3/2 cb baryons corresponding to a c -> s, d transition at the quark level. The relevance of hyperfine mixing in spin-1/2 cb baryons is shown. Our form factors are compatible with heavy quark spin symmetry constraints obtained in the infinite heavy quark mass limit.
Address [Albertus, C.] Univ Granada, Fac Ciencias, Dept Fis Atom Mol & Nucl, E-18071 Granada, Spain, Email: albertus@ugr.es;
Corporate Author Thesis
Publisher Springer Wien Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0177-7963 ISBN Medium
Area Expedition Conference
Notes WOS:000339828900036 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1865
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Author Kaskulov, M.; Hernandez, E.; Oset, E.
Title On the background in the gamma p -> omega(pi(0)gamma)p reaction and mixed event simulation Type Journal Article
Year 2010 Publication European Physical Journal A Abbreviated Journal Eur. Phys. J. A
Volume (down) 46 Issue 2 Pages 223-230
Keywords
Abstract In this paper we evaluate sources of background of the gamma p -> omega p reaction, with the omega detected through its pi(0)gamma decay channel, to compare with the experiment carried out at ELSA. We find background from gamma p -> pi(0)pi(0)p followed by decay of a pi(0) into two gamma, recombining one pi(0) and one gamma, and from the gamma p -> pi(0)eta p reaction with subsequent decay of the eta into two photons. This background accounts for the data at pi(0)gamma invariant masses beyond 700 MeV, but strength is missing at lower invariant masses which was attributed to photon misidentification events, which we simulate to get a good reproduction of the experimental background. Once this is done, we perform an event mixing simulation to reproduce the calculated background and we find that the method provides a good description of the background. A closer look reveals this is accidental. We show that the mixed event generated background in the region of the omega mass and beyond is completely tied to the events at low pi(0)gamma invariant masses where the d sigma/dM(pi 0 gamma) distribution is much larger. This has as a consequence that the mixed event method produces the same background at high invariant masses independently of the actual background in that region, as a consequence of which, the method is unsuited to give the background at energies around the peak of the omega and beyond.
Address [Kaskulov, M.] Univ Giessen, Inst Theoret Phys, D-35392 Giessen, Germany, Email: murat.kaskulov@theo.physik.uni-giessen.de
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 1434-6001 ISBN Medium
Area Expedition Conference
Notes ISI:000284869600008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 313
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Author Penalva, N.; Hernandez, E.; Nieves, J.
Title The role of right-handed neutrinos in b -> c tau (pi nu(tau), rho nu(tau), mu(nu)over-bar(mu)nu(tau))(nu)over-bar(tau) from visible final-state kinematics Type Journal Article
Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume (down) 10 Issue 10 Pages 122 - 45pp
Keywords Beyond Standard Model; CP violation
Abstract In the context of lepton flavor universality violation (LFUV) studies, we fully derive a general tensor formalism to investigate the role that left- and right-handed neutrino new-physics (NP) terms may have in b -> c tau(nu) over bar (tau) transitions. We present, for several extensions of the Standard Model (SM), numerical results for the Lambda(b) -> Lambda(c)tau(nu) over bar (tau) semileptonic decay, which is expected to be measured with precision at the LHCb. This reaction can be a new source of experimental information that can help to confirm, or maybe rule out, LFUV presently seen in (B) over bar meson decays. The present study analyzes observables that can help in distinguishing between different NP scenarios that otherwise provide very similar results for the branching ratios, which are our currently best hints for LFUV. Since the tau lepton is very short-lived, we consider three subsequent tau-decay modes, two hadronic pi nu(tau) and rho nu(tau) and one leptonic mu(nu) over bar (mu)nu(tau), which have been previously studied for (B) over bar -> D(*) decays. Within the tensor formalism that we have developed in previous works, we re-obtain the expressions for the differential decay width written in terms of visible (experimentally accessible) variables of the massive particle created in the tau decay. There are seven different tau angular and spin asymmetries that are defined in this way and that can be extracted from experiment. Those asymmetries provide observables that can help in constraining possible SM extensions.
Address [Penalva, Neus; Nieves, Juan] Ctr Mixto CSIC UV, Inst Fis Corpuscular, Inst Invest Paterna, C Catedrat Jose Beltran 2, E-46980 Valencia, 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:000708483600004 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5005
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Author Penalva, N.; Hernandez, E.; Nieves, J.
Title 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 (down) 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