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Author (down) NA64 Collaboration (Cazzaniga, C. et al); Molina Bueno, L. url  doi
openurl 
  Title Probing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel Type Journal Article
  Year 2021 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C  
  Volume 81 Issue 10 Pages 959 - 6pp  
  Keywords  
  Abstract We report the results of a search for a new vector boson (A') decaying into two dark matter particles chi 1 chi 2 of different mass. The heavier chi(2) particle subsequently decays to chi 1 and an off-shell Dark Photon A'* -> e(+)e(-). For a sufficiently largemass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in themuon anomalous magnetic moment at Fermilab. Remark- ably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained reanalyzing the previous NA64 searches for an invisible decay A' -> chi(chi) over bar and axion-like or pseudo-scalar particles -> gamma gamma. With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for A' masses from 2m(e) up to 390 MeV and mixing parameter e between 3 x 10(-5) and 2 x 10(-2).  
  Address [Cazzaniga, C.; Odagiu, P.; Depero, E.; Bueno, L. Molina; Crivelli, P.; Radics, B.; Rubbia, A.; Sieber, H.] Swiss Fed Inst Technol, Inst Particle Phys & Astrophys, CH-8093 Zurich, Switzerland, Email: Paolo.Crivelli@cern.ch  
  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:000712961200001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5013  
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  
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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) Muñoz, V.; Takhistov, V.; Witte, S.J.; Fuller, G.M. url  doi
openurl 
  Title Exploring the origin of supermassive black holes with coherent neutrino scattering Type Journal Article
  Year 2021 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 11 Issue 11 Pages 020 - 16pp  
  Keywords dark matter detectors; massive stars; neutrino astronomy; neutrino detectors  
  Abstract Collapsing supermassive stars (M greater than or similar to 3 x 10(4) M-circle dot) at high redshifts can naturally provide seeds and explain the origin of the supermassive black holes observed in the centers of nearly all galaxies. During the collapse of supermassive stars, a burst of non-thermal neutrinos is generated with a luminosity that could greatly exceed that of a conventional core collapse supernova explosion. In this work, we investigate the extent to which the neutrinos produced in these explosions can be observed via coherent elastic neutrino-nucleus scattering (CEvNS). Large scale direct dark matter detection experiments provide particularly favorable targets. We find that upcoming O(100) tonne-scale experiments will be sensitive to the collapse of individual supermassive stars at distances as large as O(10) Mpc.  
  Address [Munoz, Victor; Witte, Samuel J.] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Apartado Correos 22085, E-46071 Valencia, Spain, Email: victor.manuel.munoz@ific.uv.es;  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000765985200009 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5159  
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Author (down) Muñoz, E.; Ros, A.; Borja-Lloret, M.; Barrio, J.; Dendooven, P.; Oliver, J.F.; Ozoemelam, I.; Roser, J.; Llosa, G. doi  openurl
  Title Proton range verification with MACACO II Compton camera enhanced by a neural network for event selection Type Journal Article
  Year 2021 Publication Scientific Reports Abbreviated Journal Sci Rep  
  Volume 11 Issue 1 Pages 9325 - 12pp  
  Keywords  
  Abstract The applicability extent of hadron therapy for tumor treatment is currently limited by the lack of reliable online monitoring techniques. An active topic of investigation is the research of monitoring systems based on the detection of secondary radiation produced during treatment. MACACO, a multi-layer Compton camera based on LaBr3 scintillator crystals and SiPMs, is being developed at IFIC-Valencia for this purpose. This work reports the results obtained from measurements of a 150 MeV proton beam impinging on a PMMA target. A neural network trained on Monte Carlo simulations is used for event selection, increasing the signal to background ratio before image reconstruction. Images of the measured prompt gamma distributions are reconstructed by means of a spectral reconstruction code, through which the 4.439 MeV spectral line is resolved. Images of the emission distribution at this energy are reconstructed, allowing calculation of the distal fall-off and identification of target displacements of 3 mm.  
  Address [Munoz, Enrique; Ros, Ana; Borja-Lloret, Marina; Barrio, John; Oliver, Josep F.; Roser, Jorge; Llosa, Gabriela] Univ Valencia, Inst Fis Corpuscular IFIC, CSIC, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es  
  Corporate Author Thesis  
  Publisher Nature Research Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2045-2322 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000651603500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4836  
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