Records |
Author |
LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P. |
Title |
Observation of Photon Polarization in the b -> s gamma Transition |
Type |
Journal Article |
Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
Volume |
112 |
Issue |
16 |
Pages |
161801 - 8pp |
Keywords |
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Abstract |
This Letter presents a study of the flavor-changing neutral current radiative B-+/- -> K-+/-pi(-/+)pi(+/-)gamma decays performed using data collected in proton-proton collisions with the LHCb detector at 7 and 8 TeV center-of-mass energies. In this sample, corresponding to an integrated luminosity of 3 fb(-1), nearly 14 000 signal events are reconstructed and selected, containing all possible intermediate resonances with a K-+/-pi(-/+)pi(+/-) final state in the [1.1, 1.9] GeV/c(2) mass range. The distribution of the angle of the photon direction with respect to the plane defined by the final-state hadrons in their rest frame is studied in intervals of K-+/-pi(-/+)pi(+/-) mass and the asymmetry between the number of signal events found on each side of the plane is obtained. The first direct observation of the photon polarization in the b -> s(gamma) transition is reported with a significance of 5.2 sigma. |
Address |
[Bediaga, I.; De Miranda, J. M.; Ferreira Rodrigues, F.; Gomes, A.; Hicheur, A.; Massafferri, A.; Nasteva, I.; dos Reis, A. C.; Rodrigues, A. B.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil, Email: giovanni.veneziano@cern.ch |
Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000338513000004 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial ![sorted by Serial field, descending order (down)](img/sort_desc.gif) |
1839 |
Permanent link to this record |
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Author |
BABAR Collaboration (Lees, J.P. et al); Martinez-Vidal, F.; Oyanguren, A.; Villanueva-Perez, P. |
Title |
Measurement of the B -> X(s)l(+)l(-) Branching Fraction and Search for Direct CP Violation from a Sum of Exclusive Final States |
Type |
Journal Article |
Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
Volume |
112 |
Issue |
21 |
Pages |
211802 - 8pp |
Keywords |
|
Abstract |
We measure the total branching fraction of the flavor-changing neutral-current process B -> X(s)l(+)l(-), along with partial branching fractions in bins of dilepton and hadronic system (X-s) mass, using a sample of 471 x 10(6)Upsilon(4S) -> B (B) over bar events recorded with the BABAR detector. The admixture of charged and neutral B mesons produced at PEP-II2 are reconstructed by combining a dilepton pair with 10 different X-s final states. Extrapolating from a sum over these exclusive modes, we measure a lepton-flavor-averaged inclusive branching fraction B(B -> X(s)l(+)l(-)) = [6.73(-0.64)(+0.70)(stat)(-0.25)(+0.34)(exp syst) +/- 0.50(model syst)] x 10(-6) for m(l+l-)(2) > 0.1 GeV2/c(4). Restricting our analysis exclusively to final states from which a decaying B meson's flavor can be inferred, we additionally report measurements of the direct CP asymmetry A(CP) in bins of dilepton mass; over the full dilepton mass range, we find A(CP) = 0.04 +/- 0.11 +/- 0.01 for a leptonflavor-averaged sample. |
Address |
[Lees, J. P.; Poireau, V.; Tisserand, V.] Univ Savoie, Lab Annecy le Vieux Phys Particules LAPP, CNRS, IN2P3, F-74941 Annecy Le Vieux, France |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000338034400002 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial ![sorted by Serial field, descending order (down)](img/sort_desc.gif) |
1827 |
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Author |
ATLAS Collaboration (Aad, G. et al); Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Fassi, F.; 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.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; March, L.; Marti-Garcia, S.; Miñano, M.; 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.; Villaplana Perez, M.; Vos, M. |
Title |
Measurements of Four-Lepton Production at the Z Resonance in pp Collisions at root s=7 and 8 TeV with ATLAS |
Type |
Journal Article |
Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
Volume |
112 |
Issue |
23 |
Pages |
231806 - 18pp |
Keywords |
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Abstract |
Measurements of four-lepton (4l, l = e,mu) production cross sections at the Z resonance in pp collisions at the LHC with the ATLAS detector are presented. For dilepton and four-lepton invariant mass regions m (l+l)- > 5 GeV and 80 < m(4l) < 100 GeV, the measured cross sections are 76 +/- 18(stat) +/- 4(syst) +/- 1.4(lumi) fb and 107 +/- 9(stat) +/- 4(syst) +/- 3.0(lumi) fb at root s=7 and 8 TeV, respectively. By subtracting the nonresonant 4l production contributions and normalizing with Z -> mu(+)mu(-) events, the branching fraction for the Z boson decay to 4l is determined to be (3.20 +/- 0.25(stat) +/- 0.13(syst)) x10(-6), consistent with the standard model prediction. |
Address |
[Jackson, P.; Soni, N.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000337345600003 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial ![sorted by Serial field, descending order (down)](img/sort_desc.gif) |
1822 |
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Author |
Orrigo, S.E.A. et al; Rubio, B.; Agramunt, J.; Algora, A.; Molina, F. |
Title |
Observation of the beta-Delayed gamma-Proton Decay of Zn-56 and its Impact on the Gamow-Teller Strength Evaluation |
Type |
Journal Article |
Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
Volume |
112 |
Issue |
22 |
Pages |
222501 - 5pp |
Keywords |
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Abstract |
We report the observation of a very exotic decay mode at the proton drip line, the beta-delayed gamma-proton decay, clearly seen in the beta decay of the T-z = -2 nucleus Zn-56. Three gamma-proton sequences have been observed after the beta decay. Here this decay mode, already observed in the sd shell, is seen for the first time in the f p shell. Both. and proton decays have been taken into account in the estimation of the Fermi and Gamow-Teller strengths. Evidence for fragmentation of the Fermi strength due to strong isospin mixing is found. |
Address |
[Orrigo, S. E. A.; Rubio, B.; Agramunt, J.; Algora, A.; Molina, F.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: sonja.orrigo@ific.uv.es |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000336909200004 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial ![sorted by Serial field, descending order (down)](img/sort_desc.gif) |
1817 |
Permanent link to this record |
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Author |
Deppisch, F.F.; Harz, J.; Hirsch, M. |
Title |
Falsifying High-Scale Leptogenesis at the LHC |
Type |
Journal Article |
Year |
2014 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
Volume |
112 |
Issue |
22 |
Pages |
221601 - 5pp |
Keywords |
|
Abstract |
Measuring a nonzero value for the cross section of any lepton number violating (LNV) process would put a strong lower limit on the washout factor for the effective lepton number density in the early Universe at times close to the electroweak phase transition and thus would lead to important constraints on any high-scale model for the generation of the observed baryon asymmetry based on LNV. In particular, for leptogenesis (LG) models with masses of the right-handed neutrinos heavier than the mass scale observed at the LHC, the implied large washout factors would lead to a violation of the out-of-equilibrium condition and exponentially suppress the net lepton number produced in such LG models. We thus demonstrate that the observation of LNV processes at the LHC results in the falsification of high-scale LG models. However, no conclusions about the viability of LG models can be drawn from the nonobservation of LNV processes. |
Address |
[Deppisch, Frank F.; Harz, Julia] UCL, Dept Phys & Astron, London WC1E 6BT, England, Email: f.deppisch@ucl.ac.uk; |
Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000336920800003 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial ![sorted by Serial field, descending order (down)](img/sort_desc.gif) |
1816 |
Permanent link to this record |