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Author Hernandez, E.; Nieves, J.
Title Study of the strong Sigma(b) -> Lambda(b)pi and Sigma*(b) -> Lambda(b)pi in a nonrelativistic quark model Type Journal Article
Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 84 Issue 5 Pages 057902 - 5pp
Keywords
Abstract We present results for the strong widths corresponding to the Sigma(b) -> Lambda(b)pi and Sigma*(b) -> Lambda(b)pi decays. We apply our model from Phys. Rev. D 72, 094022 (2005), where we previously studied the corresponding transitions in the charmed sector. Our nonrelativistic constituent quark model uses wave functions that take advantage of the constraints imposed by heavy quark symmetry. The partial conservation of axial current hypothesis allows us to determine the strong vertices from an analysis of the axial current matrix elements.
Address (down) [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 WOS:000295327700002 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 776
Permanent link to this record
 
 
Author Hernandez, E.; Nieves, J.
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 (down) [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 Albertus, C.; Hernandez, E.; Nieves, J.
Title Hyperfine mixing in b -> c semileptonic decay of doubly heavy baryons Type Journal Article
Year 2010 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 683 Issue 1 Pages 21-25
Keywords
Abstract We qualitatively corroborate the results of [W. Roberts, M. Pervin, Int. J. Mod. Phys. A 24 (2009) 2401] according to which hyperfine mixing greatly affects the decay widths of b -> c semileptonic decays involving doubly heavy bc baryons. However, our predictions for the decay widths of the unmixed states differ from those reported in the work of Roberts and Pervin by a factor of 2, and this discrepancy translates to the mixed case. We further show that the predictions of heavy quark spin symmetry, might be used in the future to experimentally extract information on the admixtures in the actual physical bc baryons, in a model independent manner.
Address (down) [Hernandez, E.] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: gajatee@usal.es
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes ISI:000274129600005 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 501
Permanent link to this record
 
 
Author Hernandez, E.; Nieves, J.; Sanchez, F.; Sobczyk, J.E.
Title Tau longitudinal and transverse polarizations from visible kinematics in (anti-)neutrino nucleus scattering Type Journal Article
Year 2022 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 829 Issue Pages 137046 - 9pp
Keywords
Abstract Since the upsilon(tau) ((upsilon) over bar (tau))A(Z) -> tau(-/+) X reaction is notoriously difficult to be directly measured, the information on the dynamics of this nuclear process should be extracted from the analysis of the energy and angular distributions of the tau decay visible products. These distributions depend, in addition to d(2)sigma / (dE(tau)d cos theta(tau)), on the components of the tau-polarization vector. We give, for the first time, the general expression for the outgoing hadron (pion or rho meson) energy and angular differential cross section for the sequential upsilon(tau) A(Z) -> tau(-) (pi(-)upsilon(tau,) rho(-)upsilon(tau))X and (upsilon) over bar (tau)A(Z) -> tau(+) (pi(+)(upsilon) over bar (tau), rho(+)(upsilon) over bar (tau)) X reactions. Though all possible nuclear reaction mechanisms contribute to the distribution, it may be possible to isolate/enhance one of them by implementing appropriate selection criteria. For the case of the quasi-elastic reaction off oxygen and neutrino energies below 6 GeV, we show that the pion distributions are quite sensitive to the details of the tau-polarization components. We find significant differences between the full calculation, where the longitudinal and transverse components of the tau polarization vector vary with the energy and the scattering angle of the produced tau, and the simplified scheme in which the polarizations are set to one and zero, being the latter their respective asymptotic values reached in the high energy regime. In addition to its potential impact on neutrino oscillation analyses, this result can be used to further test different nuclear models, since these observables provide complementary information to that obtained by means of the inclusive nuclear weak charged-current differential cross section. We also study the effects on the cross section of the W-4 and W-5 nuclear structure functions, which contributions are proportional to the charged lepton mass, and therefore difficult to constrain in muon and electron neutrino experiments.
Address (down) [Hernandez, E.] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: gajatee@usal.es
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:000821534900008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5289
Permanent link to this record
 
 
Author Hernandez, E.; Nieves, J.; Valverde, M.
Title Coherent pion production off nuclei at T2K and MiniBooNE energies revisited Type Journal Article
Year 2010 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 82 Issue 7 Pages 077303 - 4pp
Keywords
Abstract As a result of a new improved fit to old bubble chamber data of the dominant axial C-5(A) nucleon-to-delta form factor, and due to the relevance of this form factor for neutrino induced coherent pion production, we reevaluate our model predictions in [Phys. Rev. D 79, 013002 ( 2009)] for different observables of the latter reaction. Central values for the total cross sections increase by 20%-30%, while differential cross sections do not change their shape appreciably. Furthermore, we also compute the uncertainties on total, differential, and flux-averaged cross sections induced by the errors in the determination of C-5(A). Our new results turn out to be compatible within about 1 sigma with the former ones. Finally, we stress the existing tension between the recent experimental determination of the sigma(CCcoh pi(+))/sigma(NCcoh pi(0)) ratio by the SciBooNE Collaboration and the theoretical predictions.
Address (down) [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:000282945200003 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 361
Permanent link to this record
 
 
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 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 (down) [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
Permanent link to this record
 
 
Author Hernandez, E.; Nieves, J.; Vicente Vacas, M.J.
Title Single pion production in neutrino-nucleus scattering Type Journal Article
Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 87 Issue 11 Pages 113009 - 11pp
Keywords
Abstract We study 1 pi production in both charged and neutral current neutrino-nucleus scattering for neutrino energies below 2 GeV. We use a theoretical model for one pion production at the nucleon level that we correct for medium effects. The results are incorporated into a cascade program that apart from production also includes the pion final state interaction inside the nucleus. Besides, in some specific channels coherent pi production is also possible and we evaluate its contribution as well. Our results for total and differential cross sections are compared with recent data from the MiniBooNE Collaboration. The model provides an overall acceptable description of the data, better for neutral-current than for charged-current channels, although the theory is systematically below the data. Differential cross sections, folded with the full neutrino flux, show that most of the missing pions lie in the forward direction and at high energies.
Address (down) [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 WOS:000320769600004 Approved no
Is ISI yes International Collaboration
Call Number IFIC @ pastor @ Serial 1485
Permanent link to this record
 
 
Author Guo, F.K.; Hidalgo-Duque, C.; Nieves, J.; Pavon Valderrama, M.
Title Consequences of heavy-quark symmetries for hadronic molecules Type Journal Article
Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 88 Issue 5 Pages 054007 - 5pp
Keywords
Abstract Among the newly observed structures in the heavy-quarkonium mass region, some have been proposed to be hadronic molecules. We investigate the consequences of heavy- quark flavor symmetry on these heavy meson hadronic molecules. The symmetry allows us to predict new hadronic molecules on one hand, and test the hadronic molecular assumption of the observed structures on the other hand. We explore the consequences of the flavor symmetry assuming the X(3872) and Z(b)(10 610) as an isoscalar D (D) over bar* and isovector B (B) over bar* hadronic molecule, respectively. A series of hadronic molecules composed of heavy mesons are predicted. In particular, there is an isoscalar 1(++) B (B) over bar* bound state with a mass about 10 580 MeV which may be searched for in the Y(1S, 2S)pi(+) pi(-) pi(0) mass distribution; the isovector charmonium partners of the Z(b)(10 610) and the Z(b)(10 650) are also predicted, which probably corresponds to the very recently observed Z(c)(3900) and Z(c)(4025) resonances by the BESIII Collaboration.
Address (down) [Guo, Feng-Kun] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, D-53115 Bonn, Germany, Email: fkguo@hiskp.uni-bonn.de;
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:000324053300003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1573
Permanent link to this record
 
 
Author Guo, F.K.; Hidalgo-Duque, C.; Nieves, J.; Pavon Valderrama, M.
Title Heavy-antiquark-diquark symmetry and heavy hadron molecules: Are there triply heavy pentaquarks? Type Journal Article
Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 88 Issue 5 Pages 054014 - 6pp
Keywords
Abstract We explore the consequences of heavy flavor, heavy quark spin, and heavy antiquark-diquark symmetries for hadronic molecules within an effective field theory framework. Owing to heavy antiquark-diquark symmetry, the doubly heavy baryons have approximately the same light-quark structure as the heavy antimesons. As a consequence, the existence of a heavy meson-antimeson molecule implies the possibility of a partner composed of a heavy meson and a doubly heavy baryon. In this regard, the D (D) over bar* molecular nature of the X(3872) will hint at the existence of several baryonic partners with isospin I = 0 and J(P) = 5(-)/2 or 3(-)/2. Moreover, if the Z(b)(10650) turns out to be a B*(B) over bar* bound state, we can be confident of the existence of Xi(bb)*(B) over bar* hadronic molecules with quantum numbers I(J(P)) = 1(1(-)/2) and I(J(P)) = 1(3/2(-)). These states are of special interest since they can be considered to be triply heavy pentaquarks.
Address (down) [Guo, Feng-Kun] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, D-53115 Bonn, Germany, Email: fkguo@hiskp.uni-bonn.de;
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:000324232700010 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1580
Permanent link to this record
 
 
Author Guo, F.K.; Hidalgo-Duque, C.; Nieves, J.; Ozpineci, A.; Pavon Valderrama, M.
Title Detecting the long-distance structure of the X(3872) Type Journal Article
Year 2014 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 74 Issue 5 Pages 2885 - 10pp
Keywords
Abstract We study the decay within a molecular picture for the state. This decay mode is more sensitive to the long-distance structure of the resonance than its and decays, which are mainly controlled by the details of the wave function at short distances. We show that the final state interaction can be important, and that a precise measurement of this partial decay width can provide valuable information on the interaction strength between the charm mesons.
Address (down) [Guo, Feng-Kun] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, D-53115 Bonn, Germany, Email: fkguo@hiskp.uni-bonn.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 1434-6044 ISBN Medium
Area Expedition Conference
Notes WOS:000340092200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1889
Permanent link to this record