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Author (down) Nadal-Gisbert, S.; Navarro-Salas, J.; Pla, S. url  doi
openurl 
  Title Low-energy states and CPT invariance at the big bang Type Journal Article
  Year 2023 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 107 Issue 8 Pages 085018 - 16pp  
  Keywords  
  Abstract In this paper, we analyze the quantum vacuum in a radiation-dominated and CPT -invariant universe by further imposing the quantum states to be ultraviolet regular i.e., satisfying the Hadamard/adiabatic condition. For scalar fields, this is enforced by constructing the vacuum via the states of low-energy proposal. For spin -12 fields, we extend this proposal for a FLRW spacetime and apply it for the radiation-dominated and CPT -invariant universe. We focus on minimizing the smeared energy density around the big bang and give strong evidence that the resulting states satisfy the Hadamard/adiabatic condition. These states are then self -consistent candidates as effective big bang quantum vacuum from the field theory perspective.  
  Address [Nadal-Gisbert, Sergi; Navarro-Salas, Jose] Univ Valencia, Ctr Mixto Univ Valencia, CSIC Fac Fis, Dept Fis Teor, Valencia 46100, Spain, Email: sergi.nadal@uv.es;  
  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:000981997800003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5585  
Permanent link to this record
 

 
Author (down) NA64 Collaboration (Andreev, Y.M. et al); Molina Bueno, L.; Tuzi, M. url  doi
openurl 
  Title Probing light dark matter with positron beams at NA64 Type Journal Article
  Year 2024 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 109 Issue 3 Pages L031103 - 6pp  
  Keywords  
  Abstract We present the results of a missing-energy search for light dark matter which has a new interaction with ordinary matter transmitted by a vector boson, called dark photon A'. For the first time, this search is performed with a positron beam by using the significantly enhanced production of A' in the resonant annihilation of positrons with atomic electrons of the target nuclei, followed by the invisible decay of A' into dark matter. No events were found in the signal region with (10.1 +/- 0.1) x 109 positrons on target with 100 GeV energy. This allowed us to set new exclusion limits that, relative to the collected statistics, prove the power of this experimental technique. This measurement is a crucial first step toward a future exploration program with positron beams, whose estimated sensitivity is here presented.  
  Address [Andreev, Yu. M.; Dermenev, A. V.; Donskov, S. V.; Dusaev, R. R.; Enik, T.; Frolov, V. N.; Kachanov, V. A.; Karneyeu, A. E.; Kirpichnikov, D. V.; Kirsanov, M. M.; Kolosov, V. N.; Gertsenberger, S. V.; Kasianova, E. A.; Kramarenko, V. A.; Kravchuk, L. V.; Krasnikov, N. V.; Lysan, V.; Matveev, V. A.; Samoylenko, V. D.; Shchukin, D.; Tikhomirov, V. O.; Tlisova, I.; Toropin, A. N.; Volkov, P. V.; Volkov, V. Yu.; Voronchikhin, I. V.; Zhevlakov, A. S.] CERN, Meyrin, Switzerland, Email: pietro.bisio@ge.infn.it  
  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:001180160500008 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 6009  
Permanent link to this record
 

 
Author (down) NA64 Collaboration (Andreev, Y.M. et al); Molina Bueno, L. url  doi
openurl 
  Title Search for pseudoscalar bosons decaying into e(+)e(-) pairs in the NA64 experiment at the CERN SPS Type Journal Article
  Year 2021 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 104 Issue 11 Pages L111102 - 5pp  
  Keywords  
  Abstract We report the results of a search for a light pseudoscalar particle a that couples to electrons and decays to e(+) e(-) perfbnned using the high-energy CERN SPS H4 electron beam. If such light pseudoscalar exists, it could explain the ATOMKI anomaly (an excess of e(+) e(-) pairs in the nuclear transitions of Be-8 and 4 He nuclei at the invariant mass similar or equal to 17 MeV observed by the experiment at the 5 MV Van de Graaff accelerator at ATOMKI, Hungary). We used the NA64 data collected in the “visible mode” configuration with a total statistics corresponding to 8.4 x 10(10) electrons on target (EOT) in 2017 and 2018. In order to increase sensitivity to small coupling parameter epsilon we also used the data collected in 2016-2018 in the “invisible mode” configuration of NA64 with a total statistics corresponding to 2.84 x 10(11) EOT. The background and efficiency estimates for these two configurations were retained from our previous analyses searching for light vector bosons and axionlike particles (ALP) (the latter were assumed to couple predominantly to gamma). In this work we recalculate the signal yields, which are different due to different cross section and lifetime of a pseudoscalar particle a, and perform a new statistical analysis. As a result, the region of the two dimensional parameter space m(a) – epsilon in the mass range from 1 to 17.1 MeV is excluded. At the mass of the central value of the ATOMKI anomaly (the first result obtained on the beryllium nucleus, 16.7 MeV) the values of epsilon in the range 2.1 x 10(-4) < epsilon < 3.2 x 10(-4) are excluded.  
  Address [Hoesgen, M.; Ketzer, B.] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, D-53115 Bonn, Germany  
  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:000738796900005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5071  
Permanent link to this record
 

 
Author (down) NA64 Collaboration (Andreev, Y.M. et al); Molina Bueno, L. url  doi
openurl 
  Title Improved exclusion limit for light dark matter from e(+) e(-) annihilation in NA64 Type Journal Article
  Year 2021 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 104 Issue 9 Pages L091701 - 7pp  
  Keywords  
  Abstract The current most stringent constraints for the existence of sub-GeV dark matter coupling to Standard Model via a massive vector boson A' were set by the NA64 experiment for the mass region m(A') less than or similar to 250 MeV, by analyzing data from the interaction of 2.84 x 10(11) 100-GeV electrons with an active thick target and searching for missing-energy events. In this work, by including A' production via secondary positron annihilation with atomic electrons, we extend these limits in the 200-300 MeV region by almost an order of magnitude, touching for the first time the dark matter relic density constrained parameter combinations. Our new results demonstrate the power of the resonant annihilation process in missing energy dark-matter searches, paving the road to future dedicated e(+) beam efforts.  
  Address [Andreev, Yu M.; Dermenev, A., V; Gninenko, S. N.; Karneyeu, A. E.; Kirpichnikov, D., V; Kirsanov, M. M.; Kravchuk, L., V; Krasnikov, N., V; Tlisova, I; Toropin, A. N.] Inst Nucl Res, Moscow 117312, Russia, Email: andrea.celentano@ge.infn.it  
  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:000744291500008 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5090  
Permanent link to this record
 

 
Author (down) NA64 Collaboration (Andreev, Y.M. et al); Molina Bueno, L. url  doi
openurl 
  Title Search for a light Z' in the L-mu – L-tau scenario with the NA64-e experiment at CERN Type Journal Article
  Year 2022 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 106 Issue 3 Pages 032015 - 12pp  
  Keywords  
  Abstract The extension of Standard Model made by inclusion of additional U(1) gauge L-mu – L-tau symmetry can explain the difference between the measured and the predicted value of the muon magnetic moment and solve the tension in B meson decays. This model predicts the existence of a new, light Z' vector boson, predominantly coupled to second and third generation leptons, whose interaction with electrons is due to a loop mechanism involving muons and taus. In this work, we present a rigorous evaluation of the upper limits in the Z' parameter space, obtained from the analysis of the data collected by the NA64-e experiment at CERN SPS, that performed a search for light dark matter with 2.84 x 10(11) electrons impinging with 100 GeV on an active thick target. The resulting limits touch the muon g – 2 preferred band for values of the Z' mass of order of 1 MeV, while the sensitivity projections for the future high-statistics NA64-e runs demonstrate the power of the electrons/positron beam approach in this theoretical scenario.  
  Address [Andreev, Yu M.; Dermenev, A., V; Gninenko, S. N.; Karneyeu, A. E.; Kirpichnikov, D., V; Kirsanov, M. M.; Kravchuk, L., V; Krasnikov, N., V; Tlisova, I; Toropin, A. N.] Inst Nucl Res, Moscow 117312, Russia, Email: luca.marsicano@ge.infn.it  
  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:000862798400003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5376  
Permanent link to this record
 

 
Author (down) Motohashi, H.; Hu, W. url  doi
openurl 
  Title Generalized slow roll in the unified effective field theory of inflation Type Journal Article
  Year 2017 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 96 Issue 2 Pages 023502 - 17pp  
  Keywords  
  Abstract We provide a compact and unified treatment of power spectrum observables for the effective field theory (EFT) of inflation with the complete set of operators that lead to second-order equations of motion in metric perturbations in both space and time derivatives, including Horndeski and Gleyzes-Langlois-Piazza-Vernizzi theories. We relate the EFT operators in ADM form to the four additional free functions of time in the scalar and tensor equations. Using the generalized slow-roll formalism, we show that each power spectrum can be described by an integral over a single source that is a function of its respective sound horizon. With this correspondence, existing model independent constraints on the source function can be simply reinterpreted in the more general inflationary context. By expanding these sources around an optimized freeze-out epoch, we also provide characterizations of these spectra in terms of five slow-roll hierarchies whose leading-order forms are compact and accurate as long as EFT coefficients vary only on time scales greater than an e-fold. We also clarify the relationship between the unitary gauge observables employed in the EFT and the comoving gauge observables of the postinflationary universe.  
  Address [Motohashi, Hayato] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, 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:000405205400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3203  
Permanent link to this record
 

 
Author (down) Motohashi, H.; Hu, W. url  doi
openurl 
  Title Primordial black holes and slow-roll violation Type Journal Article
  Year 2017 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 96 Issue 6 Pages 063503 - 9pp  
  Keywords  
  Abstract For primordial black holes (PBH) to be the dark matter in single-field inflation, the slow-roll approximation must be violated by at least O(1) in order to enhance the curvature power spectrum within the required number of e-folds between cosmic microwave background scales and PBH mass scales. Power spectrum predictions which rely on the inflaton remaining on the slow-roll attractor can fail dramatically leading to qualitatively incorrect conclusions in models like an inflection potential and misestimate the mass scale in a running mass model. We show that an optimized temporal evaluation of the Hubble slow-roll parameters to second order remains a good description for a wide range of PBH formation models where up to a 10(7) amplification of power occurs in 10 e-folds or more.  
  Address [Motohashi, Hayato] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, 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:000409436800005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3286  
Permanent link to this record
 

 
Author (down) Morisi, S.; Peinado, E. url  doi
openurl 
  Title S-4 model for quarks and leptons with maximal atmospheric angle Type Journal Article
  Year 2010 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 81 Issue 8 Pages 085015 - 8pp  
  Keywords  
  Abstract We consider a model for quark and lepton masses and mixings based on S-4 flavor symmetry. The model contains six Higgs doublets where three of them give mass to the leptons, and the other three gives mass to the quarks. Charged fermion and quark masses arise from renormalizable interactions while neutrino Majorana masses are generated through effective dimension five Weinberg operator. From the study of the minimization of the scalar potential we found a residual μ<-> tau symmetry in the neutrino sector predicting zero reactor angle and maximal atmospheric angle and for the quark sector we found a four-zero texture. We give a fit of the mass hierarchies and mixing angles in the quark sector.  
  Address [Morisi, Stefano; Peinado, Eduardo] Univ Valencia, CSIC, AHEP Grp, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: morisi@ific.uv.es  
  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:000277205000132 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ elepoucu @ Serial 461  
Permanent link to this record
 

 
Author (down) Morisi, S.; Patel, K.M.; Peinado, E. url  doi
openurl 
  Title Model for T2K indication with maximal theta(23) and trimaximal theta(12) Type Journal Article
  Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 84 Issue 5 Pages 053002 - 6pp  
  Keywords  
  Abstract Recently T2K experiment gives hint in favor of large reactor angle theta(13). Most of the models, with tribimaximal mixing at the leading order, can not reproduce such a large mixing angle since they predict typically corrections for the reactor angle of the order theta(13) similar to lambda(2)(C), where lambda(C) similar to 0.2. In this paper, we discuss the possibility to achieve large theta(13) within the T2K region with maximal atmosphericmixing angle, sin(2)theta(23) = 1/2, and trimaximal solar mixing angle, sin(2)theta(12) = 1/3, through the deviation from the exact tribimaximal mixing. We derive the structure of neutrino mass matrix that leads to the large theta(13) leaving maximal theta(23) and trimaximal theta(12). It is shown that such a structure of neutrino mass matrix can arise in a model with S(4) flavor symmetry.  
  Address [Morisi, S; Peinado, E] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, E-46071 Valencia, Spain, Email: morisi@ific.uv.es  
  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:000294567400006 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 726  
Permanent link to this record
 

 
Author (down) Morisi, S.; Nebot, M.; Patel, K.M.; Peinado, E.; Valle, J.W.F. url  doi
openurl 
  Title Quark-lepton mass relation and CKM mixing in an A(4) extension of the minimal supersymmetric standard model Type Journal Article
  Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 88 Issue 3 Pages 036001 - 8pp  
  Keywords  
  Abstract An interesting mass relation between down-type quarks and charged leptons has been recently predicted within a supersymmetric SU(3)(c) circle times SU(2)(L) circle times U(1)(Y) model based on the A(4) flavor symmetry. Here we propose a simple extension which provides an adequate full description of the quark sector. By adding a pair of vectorlike up quarks, we show how the CKM entries V-ub, V-cb, V-td and V-ts arise from deviations of the unitarity. We perform an analysis including the most relevant observables in the quark sector, such as oscillations and rare decays of kaons, B-d and B-s mesons. In the lepton sector, the model predicts an inverted hierarchy for the neutrino masses, leading to a potentially observable rate of neutrinoless double beta decay.  
  Address [Morisi, S.] Univ Wurzburg, Inst Theoret Phys & Astrophys, D-97074 Wurzburg, Germany, Email: stefano.morisi@gmail.com;  
  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:000322725800002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1520  
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