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Author (down) Sobczyk, J.E.; Hernandez, E.; Nakamura, S.X.; Nieves, J.; Sato, T.
Title Angular distributions in electroweak pion production off nucleons: Odd parity hadron terms, strong relative phases, and model dependence Type Journal Article
Year 2018 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 98 Issue 7 Pages 073001 - 39pp
Keywords
Abstract The study of pion production in nuclei is important for signal and background determinations in current and future neutrino oscillation experiments. The first step, however, is to understand the pion production reactions at the free nucleon level. We present an exhaustive study of the charged-current and neutral-current neutrino and antineutrino pion production off nucleons, paying special attention to the angular distributions of the outgoing pion. We show, using general arguments, that parity violation and time-reversal odd correlations in the weak differential cross sections are generated from the interference between different contributions to the hadronic current that are not relatively real. Next, we present a detailed comparison of three state-of-the-art, microscopic models for electroweak pion production off nucleons, and we also confront their predictions with polarized electron data, as a test of the vector content of these models. We also illustrate the importance of carrying out a comprehensive test at the level of outgoing pion angular distributions, going beyond comparisons done for partially integrated cross sections, where model differences cancel to a certain extent. Finally, we observe that all charged and neutral current distributions show sizable anisotropies, and identify channels for which parity-violating effects are clearly visible. Based on the above results, we conclude that the use of isotropic distributions for the pions in the center of mass of the final pion-nucleon system, as assumed by some of the Monte Carlo event generators, needs to be improved by incorporating the findings of microscopic calculations.
Address [Sobczyk, J. E.; Nieves, J.] Univ Valencia, Ctr Mixto CSIC, Inst Fis Corpuscular IFIC, Inst Invest Paterna, Apartado 22085, 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 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000446557200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3751
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Author (down) Saul-Sala, E.; Sobczyk, J.E.; Rafi Alam, M.; Alvarez-Ruso, L.; Nieves, J.
Title Weak kaon production off the nucleon and Watson's theorem Type Journal Article
Year 2021 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 817 Issue Pages 136349 - 7pp
Keywords
Abstract We have improved the tree-level model of Ref.[1] for weak production of kaons off nucleons by partially restoring unitarity. This is achieved by imposing Watson's theorem to the dominant vector and axial-vector contributions in appropriate angular momentum and isospin quantum number sectors. The observable consequences of this procedure are investigated.
Address [Saul-Sala, E.; Alvarez-Ruso, L.; Nieves, J.] Univ Valencia, CSIC, Ctr Mixto, Inst Invest Paterna,Dept Fis Teor, E-46071 Valencia, Spain, Email: luis.alvarez@ific.uv.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:000657652200060 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4867
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Author (down) Romanets, O.; Tolos, L.; Garcia-Recio, C.; Nieves, J.; Salcedo, L.L.; Timmermans, R.G.E.
Title Charmed and strange baryon resonances with heavy-quark spin symmetry Type Journal Article
Year 2012 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 85 Issue 11 Pages 114032 - 30pp
Keywords
Abstract We study charmed and strange baryon resonances that are generated dynamically by a unitary baryon-meson coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry breaking. The model produces resonances with negative parity from s-wave interaction of pseudoscalar and vector mesons with 1/2(+) and 3/2(+) baryons. Resonances in all the isospin, spin, and strange sectors with one, two, and three charm units are studied. Our results are compared with experimental data from several facilities, such as the CLEO, Belle or BABAR collaborations, as well as with other theoretical models. Some of our dynamically-generated states can be readily assigned to resonances found experimentally, while others do not have a straightforward identification and require the compilation of more data and also a refinement of the model. In particular, we identify the Xi(c)(2790) and Xi(c)(2815) resonances as possible candidates for a heavy-quark spin symmetry doublet.
Address [Romanets, O.; Tolos, L.; Timmermans, R. G. E.] Univ Groningen, KVI, NL-9747 AA Groningen, Netherlands
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:000305560500004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1078
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Author (down) Romanets, O.; Tolos, L.; Garcia-Recio, C.; Nieves, J.; Salcedo, L.L.; Timmermans, R.
Title Heavy-quark spin symmetry for charmed and strange baryon resonances Type Journal Article
Year 2013 Publication Nuclear Physics A Abbreviated Journal Nucl. Phys. A
Volume 914 Issue Pages 488-493
Keywords Charm; Heavy-quark spin symmetry; Dynamically generated baryon resonances
Abstract We study charmed and strange odd-parity baryon resonances that are generated dynamically by a unitary baryon-meson coupled-channels model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry breaking. The model generates resonances with negative parity from the s-wave interaction of pseudoscalar and vector mesons with 1/2(+) and 3/2(+) baryons in all the isospin, spin, and strange sectors with one, two, and three charm units. Some of our results can be identified with experimental data from several facilities, such as the CLEO, Belle, or BaBar Collaborations, as well as with other theoretical models, whereas others do not have a straightforward identification and require the compilation of more data and also a refinement of the model. (c) 2013 Elsevier B.V. All rights reserved.
Address [Romanets, Olena; Timmermans, Rob] Univ Groningen, Theory Grp, KVI, NL-9747 AA Groningen, Netherlands, Email: o.romanets@rug.nl
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 0375-9474 ISBN Medium
Area Expedition Conference
Notes WOS:000324847700069 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1601
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Author (down) Rocco, N.; Alvarez-Ruso, L.; Lovato, A.; Nieves, J.
Title Electromagnetic scaling functions within the Green's function Monte Carlo approach Type Journal Article
Year 2017 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 96 Issue 1 Pages 015504 - 12pp
Keywords
Abstract We have studied the scaling properties of the electromagnetic response functions of He-4 and C-12 nuclei computed by the Green's function Monte Carlo approach, retaining only the one-body current contribution. Longitudinal and transverse scaling functions have been obtained in the relativistic and nonrelativistic cases and compared to experiment for various kinematics. The characteristic asymmetric shape of the scaling function exhibited by data emerges in the calculations in spite of the nonrelativistic nature of the model. The results are mostly consistent with scaling of zeroth, first, and second kinds. Our analysis reveals a direct correspondence between the scaling and the nucleon-density response functions. The scaling function obtained from the proton-density response displays scaling of the first kind, even more evidently than the longitudinal and transverse scaling functions.
Address [Rocco, N.; Alvarez-Ruso, L.; Nieves, J.] Univ Valencia, CSIC, Ctr Mixto, Inst Fis Corpuscular IFIC, 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 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000406294000008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3217
Permanent link to this record
 
 
Author (down) Roca, L.; Nieves, J.; Oset, E.
Title LHCb pentaquark as a (D)over-bar*Sigma(c) – (D)over-bar*Sigma(c)* molecular state Type Journal Article
Year 2015 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 92 Issue 9 Pages 094003 - 6pp
Keywords
Abstract We perform a theoretical analysis of the Lambda(b) -> J/psi K(-)p reaction from where a recent LHCb experiment extracts a Lambda(1405) contribution in the K(-)p spectrum close to threshold and two baryon states of hidden charm in the J/psi p spectrum. We recall that baryon states of this type have been theoretically predicted matching the mass, width and J(P) of the experiment; concretely some states built up from the J/psi N, (D) over bar*Lambda(c), (D) over bar*Sigma(c), (D) over bar Sigma(c)* and (D) over bar*Sigma(c)* coupled channels. We assume that the observed narrow state around 4450 MeV has this nature and we are able to describe simultaneously the shapes and relative strength of the the K(-)p mass distribution close to threshold and the peak of the J/psi p distribution, with values of the J/psi p coupling to the resonance in line with the theoretical ones. The nontrivial matching of many properties gives support to a J(P) = 3/2(-) assignment to this state and to its nature as a molecular state mostly made of (D) over bar*Sigma(c) and (D) over bar*Sigma(c)*.
Address [Roca, L.] Univ Murcia, Dept Fis, E-30100 Murcia, 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:000364019700004 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2448
Permanent link to this record
 
 
Author (down) Penalva, N.; Hernandez, E.; Nieves, J.
Title Further tests of lepton flavor universality from the charged lepton energy distribution in b -> c semileptonic decays: The case of Lambda(b) -> Lambda(c) l(v)over-bar(l) Type Journal Article
Year 2019 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 100 Issue 11 Pages 113007 - 11pp
Keywords
Abstract In a general framework, valid for any H -> H' l(-)(v) over bar (l) semileptonic decay, we analyze the d(2)Gamma/(d omega d cos theta(l)) and d(2)Gamma/(d omega dE(l)) distributions, with omega being the product of the hadron four-velocities, theta(l) the angle made by the three-momenta of the charged lepton and the final hadron in the W- center of mass frame and E-l the charged lepton energy in the decaying hadron rest frame. Within the Standard Model (SM), d(2)Gamma/(d omega dE(l)) proportional to (c(0) (omega) c(1) (omega)E-l/M + c(2) (omega)E-l(2)/M-2), with M the initial hadron mass. We find that c(2) (omega) is independent of the lepton flavor and thus it is an ideal candidate to look for lepton flavor universality (LFU) violations. We also find a correlation between the a(2) (omega) structure function, which governs the (cos theta(l))(2) dependence of d(2)Gamma/(d omega d cos theta(l)), and c(2) (omega). Apart from trivial kinematical and mass factors, the ratio of a(2) (omega)/c(2) (omega) is a universal function that can be measured in any semileptonic decay, involving not only b -> c transitions. These two SM predictions can be used as new tests in the present search for signatures of LFU violations. We also generalize the formalism to account for some new physics (NP) terms, and show that neither c(2) nor a(2) are modified by left and right scalar NP terms, being however sensitive to left and right vector corrections. We also find that the a(2)/c(2) ratio is not modified by these latter NP contributions. Finally, and in order to illustrate our findings, we apply our general framework to the Lambda(b) -> Lambda(c)l (v) over bar (l) decay. We show that a measurement of c(2) (or a(2)) for tau decay would not only be a direct measurement of the possible existence of NP, but it would also allow to distinguish from NP fits to b -> c tau(v) over bar (tau) anomalies in the meson sector, which otherwise give the same total and differential d Gamma/d omega widths. We show that the same occurs for the other two terms, c(0) and c(1), that appear in d(2)Gamma/(d omega dE(l)), and for the cos theta(l) linear term of the angular distribution.
Address [Penalva, Neus; Nieves, Juan] Ctr Mixto CSIC UV, Inst Invest Paterna, Inst Fis Corpuscular, Apartado 22085, Valencia 46071, 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:000503400600001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4230
Permanent link to this record
 
 
Author (down) Penalva, N.; Hernandez, E.; Nieves, J.
Title Hadron and lepton tensors in semileptonic decays including new physics Type Journal Article
Year 2020 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 101 Issue 11 Pages 113004 - 24pp
Keywords
Abstract We extend our general framework for semileptonic decay, originally introduced in N. Penalva et al. [Phys. Rev. D 100, 113007 (2019)], with the addition of new physics (NP) tensor terms. In this way, all the NP effective Hamiltonians that are considered in lepton flavor universality violation (LFUV) studies have now been included. Those are left and right vector and scalar NP Hamiltonians and the NP tensor one. Besides, we now also give general expressions that allow for complex Wilson coefficients. The scheme developed is totally general and it can be applied to any charged current semileptonic decay, involving any quark flavors or initial and final hadron states. We show that all the hadronic input, including NP effects, can be parametrized in terms of 16 Lorentz scalar structure functions, constructed out of the NP complex Wilson coefficients and the genuine hadronic responses, with the latter determined by the matrix elements of the involved hadron operators. In the second part of this work, we use this formalism to obtain the complete NP effects in the Ab Acr(/ semileptonic decay, where LFUV, if finally confirmed, is also expected to be seen. We- stress the relevance of the center of mass (CM) d2F/ (dwd cos 0i) and laboratory (LAB) d2F/(dwdE,) differential decay widths, with (o the product of the hadron four-velocities, Oe the angle made by the three -momenta of the charged lepton and the final hadron in the 11/- CM frame and the charged lepton energy in the decaying hadron rest frame. While models with very different strengths in the NP terms give the same differential d17 do) and total decay widths for this decay, they predict very different numerical results for some of the cos (.),, and E coefficient -functions that determine the above two distributions. Thus, the combined analysis of the CM d2F1(dcodcos0,,) and LAB d21'/(doidE,.) differential decay widths will help clarifying what kind of NP is a better candidate in order to explain LFUV.
Address [Penalva, Neus; Hernandez, Eliecer] 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:000543941400001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4448
Permanent link to this record
 
 
Author (down) Penalva, N.; Hernandez, E.; Nieves, J.
Title (B)over-bar(c) ->eta(c),(B)over-bar(c) -> J/psi and (B)over-bar -> D-(*()) semileptonic decays including new physics Type Journal Article
Year 2020 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 102 Issue 9 Pages 096016 - 27pp
Keywords
Abstract We apply the general formalism derived by Penalva et al. [Phys. Rev. D 101, 113004 (2020)] to the semileptonic decay of pseudoscalar mesons containing a b quark. While present (B) over bar -> D-(*()) data give the strongest evidence in favor of lepton flavor universality violation, the observables that are normally considered are not able to distinguish between different new physics (NP) scenarios. In the above reference we discussed the relevant role that the various contributions to the double differential decay widths d(2)Gamma (d omega d cos theta(l)) and d(2)Gamma (d omega dE(l)) could play to this end. Here omega is the product of the two hadron fourvelocities, theta(l) is the angle made by the final lepton and final hadron three-momenta in the center of mass of the final two-lepton system, and E-l is the final charged lepton energy in the laboratory system. The formalism was applied by Penalva et al. to the analysis of the Lambda(b) -> Lambda(c) semileptonic decay, showing the new observables were able to tell apart different NP scenarios. Here we analyze the (B) over barc -> eta(c)tau(nu) over bar (tau), (B) over barc -> J/psi tau(nu) over bar (tau), (B) over bar -> D tau(nu) over bar (tau) and (B) over bar -> D*tau(nu) over bar (tau) , semileptonic decays. We find that, as a general rule, the (B) over barc -> J/psi observables, even including (tau) polarization, are less optimal for distinguishing between NP scenarios than those obtained from (B) over barc -> eta(c) decays, or those presented by Penalva et al. for the related Lambda(b) -> Lambda(c) semileptonic decay. Finally, we show that (B) over bar -> D and (B) over barc -> eta(c) , and (B) over bar -> D* and (B) over barc -> J/psi decay observables exhibit similar behaviors.
Address [Penalva, Neus; Hernandez, Eliecer] 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 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000588583900012 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4608
Permanent link to this record
 
 
Author (down) 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 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