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Author |
CDF Collaboration (Aaltonen, T. et al); Cabrera, S. |
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Title |
Search for New Bottomlike Quark Pair Decays Q(Q)over-bar -> (tW +/-)((t)over-barW +/- in Same-Charge Dileption Events |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
104 |
Issue |
9 |
Pages |
091801 - 8pp |
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Keywords  |
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Abstract |
We report the most restrictive direct limits on masses of fourth- generation down- type quarks b0, and quarklike composite fermions (B or T5= 3), decaying promptly to tW -/+. We search for a significant excess of events with two same- charge leptons (e, mu), several hadronic jets, and missing transverse energy. An analysis of data from pp collisions with an integrated luminosity of 2: 7 fb = 1 collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits mb0, mB > 338 GeV= c2 and mT5= 3 > 365 GeV= c2 at 95% confidence level. |
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Address |
[Aaltonen, T.; Mehtala, P.; Orava, R.; Osterberg, K.; Saarikko, H.; van Remortel, N.] Univ Helsinki, Dept Phys, Div High Energy Phys, FIN-00014 Helsinki, Finland |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0031-9007 |
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Notes |
ISI:000275252500010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
295 |
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Author |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
In-medium effects on K-0 mesons in relativistic heavy-ion collisions |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
82 |
Issue |
4 |
Pages |
044907 - 9pp |
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Keywords |
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Abstract |
We present the transverse momentum spectra and rapidity distributions of pi(-) and K-S(0) in Ar + KCl reactions at a beam kinetic energy of 1.756 A GeV measured with the High Acceptance Di-Electron Spectrometer (HADES). The reconstructed K-S(0) sample is characterized by good event statistics for a wide range in momentum and rapidity. We compare the experimental pi(-) and K-S(0) distributions to predictions by the Isospin Quantum Molecular Dynamics (IQMD) model. The model calculations show that K-S(0) at low transverse momenta constitute a particularly well-suited tool to investigate the kaon in-medium potential. Our K-S(0) data suggest a strong repulsive in-medium K-0 potential of about 40 MeV strength. |
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Address |
[Agakishiev, G.; Destefanis, M.; Gilardi, C.; Kirschner, D.; Kuehn, W.; Lange, J. S.; Metag, V.; Mishra, D.; Pechenov, V.; Pechenova, O.; Cavalcanti, T. Perez; Spataro, S.; Spruck, B.] Univ Giessen, Inst Phys 2, D-35392 Giessen, Germany, Email: laura.fabbietti@ph.tum.de |
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Publisher |
Amer Physical Soc |
Place of Publication |
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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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ISSN |
0556-2813 |
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Notes |
ISI:000283648400009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
334 |
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Author |
CDF Collaboration (Aaltonen, T. et al); Cabrera, S. |
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Title |
Measurement of the top quark mass in the dilepton channel using m(T2) at CDF |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
3 |
Pages |
031102 - 9pp |
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Keywords |
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Abstract |
We present measurements of the top quark mass using m(T2), a variable related to the transverse mass in events with two missing particles. We use the template method applied to t (t) over bar dilepton events produced in p (p) over bar collisions at Fermilab's Tevatron Collider and collected by the CDF detector. From a data sample corresponding to an integrated luminosity of 3.4 fb(-1), we select 236 t (t) over bar candidate events. Using the m(T2) distribution, we measure the top quark mass to be M-top = 168.0(-4.0)(4.8)(stat) +/- 2.9(syst) GeV/c(2). By combining m(T2) with the reconstructed top quark mass distributions based on a neutrino weighting method, we measure M-top = 169.3 +/- 2.7(stat) +/- 3.2(syst) GeV/c(2). This is the first application of the m(T2) variable in a mass measurement at a hadron collider. |
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Address |
[Aaltonen, T.; Mehtala, P.; Orava, R.; Osterberg, K.; Saarikko, H.; van Remortel, N.] Univ Helsinki, Div High Energy Phys, Dept Phys, FIN-00014 Helsinki, Finland |
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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 |
1550-7998 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000275069000002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
296 |
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Author |
Aguilar-Saavedra, J.A.; Bernabeu, J. |
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Title |
W polarisation beyond helicity fractions in top quark decays |
Type |
Journal Article |
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Year |
2010 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
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Volume |
840 |
Issue |
1-2 |
Pages |
349-378 |
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Keywords |
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Abstract |
We calculate the density matrix for the decay of a polarised top quark into a polarised W boson and a massive 17 quark, for the most general Wth vertex arising from dimension-six gauge-invariant effective operators. We show that, in addition to the well-known W helicity fractions, for polarised top decays it is worth defining and studying the transverse and normal W polarisation fractions, that is, the W polarisation alone two directions orthogonal to its momentum. In particular, a rather simple forward-backward asymmetry in the normal direction is found to be very sensitive to complex phases in one of the Wth anomalous couplings. This asymmetry, which indicates a normal W polarisation, can be generated for example by a P-odd. T-odd transition electric dipole moment. We also investigate the angular distribution of decay products in the top quark rest frame, calculating the spin analysing powers for a general Wth vertex. Finally we show that, using a combined fit to top decay observables and the t W cross section, at LHC it will be possible to obtain model-independent measurements of all the (complex) Wth couplings as well as the single top polarisation. Implications for spin correlations in top pair production are also discussed. |
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Address |
[Aguilar-Saavedra, J. A.] Univ Granada, Dept Fis Teor & Cosmos, E-18071 Granada, Spain, Email: jaas@ugr.es |
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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 |
0550-3213 |
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Conference |
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Notes |
ISI:000281832900013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
370 |
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Author |
Sanjuan, R.; Nebot, M.; Chirico, N.; Mansky, L.M.; Belshaw, R. |
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Title |
Viral Mutation Rates |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Virology |
Abbreviated Journal |
J. Virol. |
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Volume |
84 |
Issue |
19 |
Pages |
9733-9748 |
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Keywords |
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Abstract |
Accurate estimates of virus mutation rates are important to understand the evolution of the viruses and to combat them. However, methods of estimation are varied and often complex. Here, we critically review over 40 original studies and establish criteria to facilitate comparative analyses. The mutation rates of 23 viruses are presented as substitutions per nucleotide per cell infection (s/n/c) and corrected for selection bias where necessary, using a new statistical method. The resulting rates range from 10(-8) to 10(-6) s/n/c for DNA viruses and from 10(-6) to 10(-4) s/n/c for RNA viruses. Similar to what has been shown previously for DNA viruses, there appears to be a negative correlation between mutation rate and genome size among RNA viruses, but this result requires further experimental testing. Contrary to some suggestions, the mutation rate of retroviruses is not lower than that of other RNA viruses. We also show that nucleotide substitutions are on average four times more common than insertions/deletions (indels). Finally, we provide estimates of the mutation rate per nucleotide per strand copying, which tends to be lower than that per cell infection because some viruses undergo several rounds of copying per cell, particularly double-stranded DNA viruses. A regularly updated virus mutation rate data set will be available at www.uv.es/rsanjuan/virmut. |
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Address |
[Sanjuan, Rafael] Univ Valencia, Inst Cavanilles Biodiversitat & Biol Evolutiva, Dept Genet, Valencia 46980, Spain, Email: rafael.sanjuan@uv.es |
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Corporate Author |
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Publisher |
Amer Soc Microbiology |
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 |
0022-538x |
ISBN |
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Area |
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Conference |
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Notes |
ISI:000282641800008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
371 |
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| Permanent link to this record |
