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Author |
Gomez Dumm, D.; Noguera, S.; Scoccola, N.N. |
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Title |
Pion radiative weak decays in nonlocal chiral quark models |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
698 |
Issue |
3 |
Pages |
236-242 |
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Keywords |
Nonlocal quark models; Pion radiative weak decays |
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Abstract |
We analyze the radiative pion decay pi(+) -> e(+) nu(e)gamma within nonlocal chiral quark models that include wave function renormalization. In this framework we calculate the vector and axial-vector form factors F-V and F-A at q(2) = 0 – where q(2) is the e(+) nu(e) squared invariant mass – and the slope a of F-V (q(2)) at q(2) -> 0. The calculations are carried out considering different nonlocal form factors, in particular those taken from lattice QCD evaluations, showing a reasonable agreement with the corresponding experimental data. The comparison of our results with those obtained in the (local) NJL model and the relation of F-V and a with the form factor in pi(0) -> gamma*gamma decays are discussed. |
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Address |
[Gomez Dumm, D.] Univ Nacl La Plata, CONICET, Dept Fis, IFLP, RA-1900 La Plata, Buenos Aires, Argentina, Email: dumm@fisica.unlp.edu.ar |
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Publisher |
Elsevier Science Bv |
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English |
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Original Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
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Conference |
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Notes  |
ISI:000289543700008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
609 |
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Author |
Abgrall, N. et al; Cervera-Villanueva, A.; Escudero, L.; Monfregola, L.; Stamoulis, P. |
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Title |
Time projection chambers for the T2K near detectors |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
637 |
Issue |
1 |
Pages |
25-46 |
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Keywords |
Time projection chamber; Drift chamber; Gas system; Micromegas; Neutrino oscillation |
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Abstract |
The T2K experiment is designed to study neutrino oscillation properties by directing a high intensity neutrino beam produced at J-PARC in Tokai, Japan, towards the large Super-Kamiokande detector located 295 km away, in Kamioka, Japan. The experiment includes a sophisticated near detector complex, 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to better understand neutrino interactions at the energy scale below a few GeV. A key element of the near detectors is the ND280 tracker, consisting of two active scintillator-bar target systems surrounded by three large time projection chambers (TPCs) for charged particle tracking. The data collected with the tracker are used to study charged current neutrino interaction rates and kinematics prior to oscillation, in order to reduce uncertainties in the oscillation measurements by the far detector. The tracker is surrounded by the former UA1/NOMAD dipole magnet and the TPCs measure the charges, momenta, and particle types of charged particles passing through them. Novel features of the TPC design include its rectangular box layout constructed from composite panels, the use of bulk micromegas detectors for gas amplification, electronics readout based on a new ASIC, and a photoelectron calibration system. This paper describes the design and construction of the TPCs, the micromegas modules, the readout electronics, the gas handling system, and shows the performance of the TPCs as deduced from measurements with particle beams, cosmic rays, and the calibration system. |
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Address |
[Birney, P.; Bojechko, C.; Fransham, K.; Gaudin, A.; Karlen, D.; Langstaff, R.; Lenckowski, M.; Myslik, J.; Poffenberger, P.; Roney, M.; Tvaskis, V.] Univ Victoria, Dept Phys & Astron, Victoria, BC, Canada, Email: karlen@uvic.ca |
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Publisher |
Elsevier Science Bv |
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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 |
0168-9002 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000289608000004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
607 |
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Author |
Andricek, L. et al; Lacasta, C.; Marinas, C.; Vos, M. |
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Title |
Intrinsic resolutions of DEPFET detector prototypes measured at beam tests |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
638 |
Issue |
1 |
Pages |
24-32 |
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Keywords |
Silicon pixel detector; Detector resolution; Spatial resolution; DEPFET; Beam test |
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Abstract |
The paper is based on the data of the 2009 DEPFET beam test at CERN SPS. The beam test used beams of pions and electrons with energies between 40 and 120 GeV, and the sensors tested were prototypes with thickness of 450 μm and pixel pitch between 20 and 32 μm. Intrinsic resolutions of the detectors are calculated by disentangling the contributions of measurement errors and multiple scattering in tracking residuals. Properties of the intrinsic resolution estimates and factors that influence them are discussed. For the DEPFET detectors in the beam test, the calculation yields intrinsic resolutions of approximate to 1 μm, with a typical accuracy of 0.1 μm. Bias scan, angle scan, and energy scan are used as example studies to show that the intrinsic resolutions are a useful tool in studies of detector properties. With sufficiently precise telescopes, detailed resolution maps can be constructed and used to study and optimize detector performance. |
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Address |
[Dolezal, Z.; Drasal, Z.; Kodys, P.; Kvasnicka, P.; Malina, L.; Scheirich, J.] Charles Univ Prague, Fac Math & Phys, Inst Particle & Nucl Phys, CR-18000 Prague, Czech Republic, Email: peter.kodys@mff.cuni.cz |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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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 |
0168-9002 |
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 |
ISI:000290082600005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
618 |
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Author |
AGATA Collaboration (Soderstrom, P.A. et al); Gadea, A. |
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Title |
Interaction position resolution simulations and in-beam measurements of the AGATA HPGe detectors |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
638 |
Issue |
1 |
Pages |
96-109 |
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Keywords |
gamma-ray tracking; AGATA; Monte Carlo simulations; HPGe detectors; Fusion-evaporation reactions |
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Abstract |
The interaction position resolution of the segmented HPGe detectors of an AGATA triple cluster detector has been studied through Monte Carlo simulations and in an in-beam experiment. A new method based on measuring the energy resolution of Doppler-corrected gamma-ray spectra at two different target to detector distances is described. This gives the two-dimensional position resolution in the plane perpendicular to the direction of the emitted gamma-ray. The gamma-ray tracking was used to determine the full energy of the gamma-rays and the first interaction point, which is needed for the Doppler correction. Five different heavy-ion induced fusion-evaporation reactions and a reference reaction were selected for the simulations. The results of the simulations show that the method works very well and gives a systematic deviation of <1 mm in the FVVHM of the interaction position resolution for the gamma-ray energy range from 60 keV to 5 MeV. The method was tested with real data from an in-beam measurement using a (30)5i beam at 64 MeV on a thin C-12 target. Pulse-shape analysis of the digitized detector waveforms and gamma-ray tracking was performed to determine the position of the first interaction point, which was used for the Doppler corrections. Results of the dependency of the interaction position resolution on the gamma-ray energy and on the energy, axial location and type of the first interaction point, are presented. The FVVHM of the interaction position resolution varies roughly linearly as a function of gamma-ray energy from 8.5 mm at 250 key to 4 mm at 1.5 MeV, and has an approximately constant value of about 4 mm in the gamma-ray energy range from 1.5 to 4 MeV. |
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Address |
[Soderstrom, P. -A.; Nyberg, J.; Al-Adili, A.; Atac, A.; Veyssiere, C.] Uppsala Univ, Dept Phys & Astron, SE-75121 Uppsala, Sweden, Email: P-A.Soderstrom@physics.uu.se |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
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 |
0168-9002 |
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 |
ISI:000290082600015 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
619 |
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Author |
Bartl, A.; Eberl, H.; Herrmann, B.; Hidaka, K.; Majerotto, W.; Porod, W. |
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Title |
Impact of squark generation mixing on the search for squarks decaying into fermions at LHC |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
698 |
Issue |
5 |
Pages |
380-388 |
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Keywords |
Supersymmetry; Squark; Flavour violation; LHC |
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Abstract |
We study the effect of squark generation mixing on squark production and decays at LHC in the Minimal Supersymmetric Standard Model (MSSM). We show that the effect can be very large despite the very strong constraints on quark-flavour violation (QFV) from experimental data on B mesons. We find that the two lightest up-type squarks (u) over bar (1.2) can have large branching ratios for the decays into c (chi) over bar (0)(1) and t (chi) over bar (0)(1) at the same time due to squark generation mixing, leading to QFV signals 'pp -> c (t) over bar (t (c) over bar) + missing-E-T + X' with a significant rate. The observation of this remarkable signature would provide a powerful test of supersymmetric QFV at LHC. This could have a significant impact on the search for squarks and the determination of the underlying MSSM parameters. |
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Address |
[Hidaka, K.] Tokyo Gakugei Univ, Dept Phys, Tokyo 1848501, Japan, Email: hidaka@u-gakugei.ac.jp |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
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 |
0370-2693 |
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 |
ISI:000290185500005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
630 |
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| Permanent link to this record |
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Author |
Sajjad Athar, M.; Ruiz Simo, I.; Vicente Vacas, M.J. |
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Title |
Nuclear medium modification of the F2(x, Q^2) structure function |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Physics A |
Abbreviated Journal |
Nucl. Phys. A |
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Volume |
857 |
Issue |
1 |
Pages |
29-41 |
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Keywords |
Structure function; Nuclear medium effects; Deep inelastic scattering; Local density approximation |
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Abstract |
We study the nuclear effects in the electromagnetic structure function F-2(x, Q(2)) in the deep inelastic lepton nucleus scattering process by taking into account Fermi motion, binding, pion and rho meson cloud contributions. Calculations have been done in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations. The ratios R-F2(A) (x, Q(2)) = 2F(2)(A)(x, Q(2))/AF(2)(D)(x, Q(2)) are obtained and compared with recent JLab results for light nuclei with special attention to the slope of the x distributions. This magnitude shows a non-trivial A dependence and it is insensitive to possible normalization uncertainties. The results have also been compared with some of the older experiments using intermediate mass nuclei. |
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Address |
[Athar, M. Sajjad] Aligarh Muslim Univ, Dept Phys, Aligarh 202002, Uttar Pradesh, India, Email: sajathar@gmail.com |
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Corporate Author |
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Publisher |
Elsevier Science Bv |
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 |
0375-9474 |
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 |
ISI:000290607500004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
627 |
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Author |
Fernandez-Carames, T.; Valcarce, A.; Vijande, J. |
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Title |
Doubly charmed exotic mesons: A gift of nature? |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
699 |
Issue |
4 |
Pages |
291-295 |
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Keywords |
Exotic mesons; Quark model; Multiquark states |
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Abstract |
We study doubly charmed exotic states by solving the scattering problem of two D mesons. Our results point to the existence of a stable isoscalar doubly charmed meson with quantum numbers (I)J(P) = (0)1(+). We perform a thorough comparison to the results obtained within the hyperspherical harmonic formalism. Such exotic states could be measured at LHC and RHIC. Their experimental observation would, for the first time, confirm the contribution of multiquark structures to hadron spectroscopy. |
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Address |
[Carames, T. F.; Valcarce, A.] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: valcarce@usal.es |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
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 |
0370-2693 |
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 |
ISI:000291073200016 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
634 |
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| Permanent link to this record |
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Author |
Baker, M.J.; Bordes, J.; Hong-Mo, C.; Tsun, T.S. |
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Title |
Mass Hierarchy, Mixing, CP-Violation And Higgs Decay – Or Why Rotation Is Good For Us |
Type |
Journal Article |
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Year |
2011 |
Publication |
International Journal of Modern Physics A |
Abbreviated Journal |
Int. J. Mod. Phys. A |
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Volume |
26 |
Issue |
13 |
Pages |
2087-2124 |
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Keywords |
Quark and lepton mixing; mass hierarchy; CP violation; rotation |
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Abstract |
The idea of a rank-one rotating mass matrix (R2M2) is reviewed detailing how it leads to ready explanations both for the fermion mass hierarchy and for the distinctive mixing patterns between up and down fermion states, which can be and have been tested against experiment and shown to be fully consistent with existing data. Further, R2M2 is seen to offer, as by-products: (i) a new solution to the strong CP problem in QCD by linking the theta-angle there to the Kobayashi-Maskawa CP-violating phase in the CKM matrix, and (ii) some novel predictions of possible anomalies in Higgs decay observable in principle at the LHC. A special effort is made to answer some questions raised. |
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Address |
[Baker, Michael J.; Tsun, Tsou Sheung] Univ Oxford, Inst Math, Oxford OX1 3LB, England, Email: bakerm@maths.ox.ac.uk |
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Corporate Author |
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Thesis |
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Publisher |
World Scientific Publ Co Pte Ltd |
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 |
0217-751x |
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 |
ISI:000291219600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
643 |
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| Permanent link to this record |
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Author |
Villaescusa-Navarro, F.; Dalal, N. |
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Title |
Cores and cusps in warm dark matter halos |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
024 - 16pp |
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Keywords |
dark matter theory; dark matter simulations; dwarfs galaxies; rotation curves of galaxies |
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Abstract |
The apparent presence of large core radii in Low Surface Brightness galaxies has been claimed as evidence in favor of warm dark matter. Here we show that WDM halos do not have cores that are large fractions of the halo size: typically, r(core)/r(200) less than or similar to 10(-3). This suggests an astrophysical origin for the large cores observed in these galaxies, as has been argued by other authors. |
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Address |
[Villaescusa-Navarro, Francisco] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: villa@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
1475-7516 |
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 |
ISI:000291258300024 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
641 |
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| Permanent link to this record |
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Author |
Mangano, G.; Miele, G.; Pastor, S.; Pisanti, O.; Sarikas, S. |
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Title |
Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis |
Type |
Journal Article |
| |
Year |
2011 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
035 - 18pp |
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Keywords |
big bang nucleosynthesis; neutrino properties; cosmological neutrinos; physics of the early universe |
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Abstract |
The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos N-eff. This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. In the present analysis we determine the upper bounds that BBN places on N-eff from primordial neutrino-antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations. We consider quite a wide range for the total lepton number in the neutrino sector, eta(nu) = eta(nu e) + eta(nu mu) + eta(nu tau) and the initial electron neutrino asymmetry eta(in)(nu e), solving the corresponding kinetic equations which rule the dynamics of neutrino (antineutrino) distributions in phase space due to collisions, pair processes and flavor oscillations. New bounds on both the total lepton number in the neutrino sector and the nu(e)-(nu) over bar (e) asymmetry at the onset of BBN are obtained fully exploiting the time evolution of neutrino distributions, as well as the most recent determinations of primordial H-2/H density ratio and He-4 mass fraction. Note that taking the baryon fraction as measured by WMAP, the H-2/H abundance plays a relevant role in constraining the allowed regions in the eta(nu)-eta(in)(nu e) plane. These bounds fix the maximum contribution of neutrinos with primordial asymmetries to N-eff as a function of the mixing parameter theta(13), and point out the upper bound N-eff less than or similar to 3.4. Comparing these results with the forthcoming measurement of N-eff by the Planck satellite will likely provide insight on the nature of the radiation content of the universe. |
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Address |
[Mangano, Gianpiero; Miele, Gennaro; Pisanti, Ofelia; Sarikas, Srdjan] Ist Nazl Fis Nucl, Sez Napoli, I-80126 Naples, Italy, Email: mangano@na.infn.it |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
1475-7516 |
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 |
ISI:000291258300035 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
642 |
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| Permanent link to this record |
