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Author NEXT Collaboration (Cebrian, S. et al); Alvarez, V.; Carcel, S.; Cervera-Villanueva, A.; Diaz, J.; Ferrario, P.; Gomez-Cadenas, J.J.; Laing, A.; Liubarsky, I.; Lopez-March, N.; Lorca, D.; Martin-Albo, J.; Martinez, A.; Monrabal, F.; Monserrate, M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Rodriguez, J.; Serra, L.; Simon, A.; Sorel, M.; Yahlali, N.
Title (up) Accurate gamma and MeV-electron track reconstruction with an ultra-low diffusion Xenon/TMA TPC at 10 atm Type Journal Article
Year 2015 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 804 Issue Pages 8-24
Keywords Double-beta decay; Gamma and electron detection; Microbulk micromegas; Time projection chamber; High pressure Xenon-Trimehylamine; Penning-Fluorescent mixtures
Abstract We report the performance of a 10 atm Xenon/trimethylamine time projection chamber (TPC) for the detection of X-rays (30 keV) and gamma-rays (0.511-1.275 MeV) in conjunction with the accurate tracking of the associated electrons. When operated at such a high pressure and in similar to 1%-admixtures, trimethylamine (TMA) endows Xenon with an extremely low electron diffusion (1.3 +/- 0.13 mm-sigma (longitudinal), 0.95 +/- 0.20 mm-sigma (transverse) along 1 m drift) besides forming a convenient Penning-Fluorescent' mixture. The TPC, that houses 1.1 kg of gas in its fiducial volume, operated continuously for 100 live-days in charge amplification mode. The readout was performed through the recently introduced microbulk Micromegas technology and the AFTER chip, providing a 3D voxelization of 8 mm x 8 mm x 1.2 mm for approximately 10 cm/MeV-long electron tracks. Resolution in energy (epsilon) at full width half maximum (R) inside the fiducial volume ranged from R = 14.6% (30 keV) to R = 4.6% (1.275 MeV). This work was developed as part of the R&D program of the NEXT collaboration for future detector upgrades in the search of the neutrino-less double beta decay (beta beta 0 nu) in Xe-136, specifically those based on novel gas mixtures. Therefore we ultimately focus on the calorimetric and topological properties of the reconstructed MeV-electron tracks. In particular, the obtained energy resolution has been decomposed in its various contributions and improvements towards achieving the R =1.4%root MeV/epsilon levels obtained in small sensors are discussed.
Address [Gonzalez-Diaz, Diego; Cebrian, S.; Dafni, T.; Herrera, D. C.; Irastorza, I. G.; Luzon, G.; Villar, J. A.; Aznarab, F.; Castel, J.; Garcia, J. A.; Gomez, H.; Iguaz, F. J.; Lagraba, A.; Rodriguez, A.; Ruiz-Choliz, E.; Segui, L.; Tomas, A.] Univ Zaragoza, Lab Fis Nucl & Astroparticulas, Zaragoza, Spain, Email: Diego.Gonzalez.Diaz@cern.ch;
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 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000364133700002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2442
Permanent link to this record
 
 
Author LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C.
Title (up) Amplitude analysis of B-0 -> (D)over-bar0K(+)pi(-) decays Type Journal Article
Year 2015 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 92 Issue 1 Pages 012012 - 24pp
Keywords
Abstract The Dalitz plot distribution of B-0 -> (D) over bar K-0(+)pi(-) decays is studied using a data sample corresponding to 3.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate K* (892)(0), K*(1410)(0), K-2*(1430)(0) and D-2(*)(2460)(-) resonances. The model also contains components to describe broad structures, including the K-0(*)(1430)(0) and D-0(*)(2400)(-) resonances, in the K pi S-wave and the D pi S-and P-waves. The masses and widths of the D-0*(2400)(-) and D-2(*)(2460)(-) resonances are measured, as are the complex amplitudes and fit fractions for all components included in the amplitude model. The model obtained will be an integral part of a future determination of the angle gamma of the Cabibbo-Kobayashi-Maskawa quark mixing matrix using B-0 -> DK+pi(-) decays.
Address [Bediaga, I.; De Miranda, J. M.; Dordei, F.; Ferreira Rodrigues, F.; Gomes, A.; Massafferri, A.; Osorio Rodrigues, B.; dos Reis, A. C.; Rodrigues, A. B.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil
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:000358256700002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2310
Permanent link to this record
 
 
Author NEXT Collaboration (Serra, L. et al); Sorel, M.; Alvarez, V.; Carcel, S.; Cervera-Villanueva, A.; Diaz, J.; Ferrario, P.; Gomez-Cadenas, J.J.; Laing, A.; Liubarsky, I.; Lopez-March, N.; Lorca, D.; Martin-Albo, J.; Martinez, A.; Monrabal, F.; Monserrate, M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Querol, M.; Renner, J.; Rodriguez, J.; Simon, A.; Yahlali, N.
Title (up) An improved measurement of electron-ion recombination in high-pressure xenon gas Type Journal Article
Year 2015 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.
Volume 10 Issue Pages P03025 - 21pp
Keywords Charge transport, multiplication and electroluminescence in rare gases and liquids; Double-beta decay detectors; Time projection chambers; Ionization and excitation processes
Abstract We report on results obtained with the NEXT-DEMO prototype of the NEXT-100 high-pressure xenon gas time projection chamber (TPC), filled with pure xenon gas at 10 bar pressure and exposed to an alpha decay calibration source. Compared to our previous measurements with alpha particles, an upgraded detector and improved analysis techniques have been used. We measure event-by-event correlated fluctuations between ionization and scintillation due to electronion recombination in the gas, with correlation coefficients between -0.80 and -0.56 depending on the drift field conditions. By combining the two signals, we obtain a 2.8% FWHM energy resolution for 5.49 MeV alpha particles and a measurement of the optical gain of the electroluminescent TPC. The improved energy resolution also allows us to measure the specific activity of the radon in the gas due to natural impurities. Finally, we measure the average ratio of excited to ionized atoms produced in the xenon gas by alpha particles to be 0.561 +/- 0.045, translating into an average energy to produce a primary scintillation photon of W-ex = (39.2 +/- 3.2) eV.
Address [Serra, L.; Sorel, M.; Alvarez, V.; Carcel, S.; Cervera, A.; Diaz, J.; Ferrario, P.; Gomez-Cadenas, J. J.; Laing, A.; Liubarsky, I.; Lopez-March, N.; Lorca, D.; Martin-Albo, J.; Martinez, A.; Monrabal, F.; Monserrate, M.; Munoz Vidal, J.; Nebot-Guinot, M.; Querol, M.; Renner, J.; Rodriguez, J.; Simon, A.; Yahlali, N.] CSIC, Inst Fis Corpuscular IFIC, Valencia 46980, Spain, Email: luis.serra@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 1748-0221 ISBN Medium
Area Expedition Conference
Notes WOS:000357944500075 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2307
Permanent link to this record
 
 
Author Celis, A.; Fuentes-Martin, J.; Serodio, H.
Title (up) An invisible axion model with controlled FCNCs at tree level Type Journal Article
Year 2015 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 741 Issue Pages 117-123
Keywords
Abstract We derive the necessary conditions to build a class of invisible axion models with Flavor Changing Neutral Currents at tree-level controlled by the fermion mixing matrices and present an explicit model implementation. A horizontal Peccei-Quinn symmetry provides a solution to the strong CP problem via the Peccei-Quinn mechanism and predicts a cold dark mater candidate, the invisible axion or familon. The smallness of active neutrino masses can be explained via a type I seesaw mechanism, providing a dynamical origin for the heavy seesaw scale. The possibility to avoid the domain wall problem stands as one of the most interesting features of the type of models considered. Experimental limits relying on the axion-photon coupling, astrophysical considerations and familon searches in rare kaon and muon decays are discussed.
Address [Celis, Alejandro; Fuentes-Martin, Javier; Serodio, Hugo] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain, Email: alejandro.celis@ific.uv.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 WOS:000348290800016 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2108
Permanent link to this record
 
 
Author ATLAS Collaboration (Aad, G. et al); Alvarez Piqueras, D.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Jimenez Pena, J.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Mitsou, V.A.; Moles-Valls, R.; Oliver Garcia, E.; Pedraza Lopez, S.; Perez Garcia-Estañ, M.T.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Vos, M.
Title (up) Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at p root s=8 TeV with the ATLAS detector Type Journal Article
Year 2015 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 10 Issue 10 Pages 150 - 51pp
Keywords Exotics; Lepton production; Hadron-Hadron Scattering; Beyond Standard Model; vector-like quarks; four-top-production; chiral b'; same charge top pair
Abstract An analysis is presented of events containing jets including at least one b tagged jet, sizeable missing transverse momentum, and at least two leptons including a pair of the same electric charge, with the scalar sum of the jet and lepton transverse momenta being large. A data sample with an integrated luminosity of 20.3 fb(-1) of p p collisions at p root s = 8TeV recorded by the ATLAS detector at the Large Hadron Collider is used. Standard Model processes rarely produce these final states, but there are several models of physics beyond the Standard Model that predict an enhanced rate of production of such events; the ones considered here are production of vector-like quarks, enhanced fourtop- quark production, pair production of chiral b'-quarks, and production of two positively charged top quarks. Eleven signal regions are defined; subsets of these regions are combined when searching for each class of models. In the three signal regions primarily sensitive to positively charged top quark pair production, the data yield is consistent with the background expectation. There are more data events than expected from background in the set of eight signal regions defined for searching for vector-like quarks and chiral b'-quarks, but the significance of the discrepancy is less than two standard deviations. The discrepancy reaches 2.5 standard deviations in the set of five signal regions defined for searching for four-top-quark production. The results are used to set 95% CL limits on various models.
Address [Jackson, P.; Lee, L.; Soni, N.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia
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:000373570900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2615
Permanent link to this record