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Measurement of the Bs0-BÌ„s0 oscillation frequency

Physical Review Letters 97:6 (2006)

Authors:

A Abulencia, D Acosta, J Adelman, T Affolder, T Akimoto, MG Albrow, D Ambrose, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antos, M Aoki, G Apollinari, JF Arguin, T Arisawa, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, A Belloni, E Ben Haim, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, A Boveia, B Brau, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, J Chapman, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, PH Chu, SH Chuang, K Chung, WH Chung, YS Chung, M Ciljak

Abstract:

We present the first precise measurement of the Bs0-B̄s0 oscillation frequency Δms. We use 1fb-1 of data from pp̄ collisions at s=1.96TeV collected with the CDF II detector at the Fermilab Tevatron. The sample contains signals of 3600 fully reconstructed hadronic Bs decays and 37000 partially reconstructed semileptonic Bs decays. We measure the probability as a function of proper decay time that the Bs decays with the same, or opposite, flavor as the flavor at production, and we find a signal consistent with Bs0-B̄s0 oscillations. The probability that random fluctuations could produce a comparable signal is 0.2%. Under the hypothesis that the signal is due to Bs0-B̄s0 oscillations, we measure Δms=17.31-0.18+0.33(stat)±0. 07(syst)ps-1 and determine |Vtd/Vts|=0.208-0.002+0.001(expt)-0.006+0.008(theor). © 2006 The American Physical Society.

The rapid formation of a large rotating disk galaxy three billion years after the Big Bang

Nature 442:7104 (2006) 786-789

Authors:

R Genzel, LJ Tacconi, F Eisenhauer, NM Förster Schreiber, A Cimatti, E Daddi, N Bouché, R Davies, MD Lehnert, D Lutz, N Nesvadba, A Verma, R Abuter, K Shapiro, A Sternberg, A Renzini, X Kong, N Arimoto, M Mignoli

Abstract:

Observations and theoretical simulations have established a framework for galaxy formation and evolution in the young Universe. Galaxies formed as baryonic gas cooled at the centres of collapsing dark-matter haloes; mergers of haloes and galaxies then led to the hierarchical build-up of galaxy mass. It remains unclear, however, over what timescales galaxies were assembled and when and how bulges and disks - the primary components of present-day galaxies - were formed. It is also puzzling that the most massive galaxies were more abundant and were forming stars more rapidly at early epochs than expected from models. Here we report high-angular-resolution observations of a representative luminous star-forming galaxy when the Universe was only 20% of its current age. A large and massive rotating protodisk is channelling gas towards a growing central stellar bulge hosting an accreting massive black hole. The high surface densities of gas, the high rate of star formation and the moderately young stellar ages suggest rapid assembly, fragmentation and conversion to stars of an initially very gas-rich protodisk, with no obvious evidence for a major merger. © 2006 Nature Publishing Group.

A radio-emitting outflow in the quiescent state of A0620−00: implications for modelling low-luminosity black hole binaries

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 370:3 (2006) 1351-1360

Authors:

E Gallo, RP Fender, JCA Miller-Jones, A Merloni, PG Jonker, S Heinz, TJ Maccarone, M Van Der Klis

A search for t → τ ν q in t over(t, ̄) production

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 639:3-4 (2006) 172-178

Authors:

A Abulencia, D Acosta, J Adelman, T Affolder, T Akimoto, MG Albrow, D Ambrose, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antos, M Aoki, G Apollinari, JF Arguin, T Arisawa, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, A Belloni, E Ben-Haim, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, S Bourov, A Boveia, B Brau, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carron, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, J Chapman, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, PH Chu, SH Chuang, K Chung, WH Chung

Abstract:

We present a search for t over(t, ̄) events with a tau lepton in the final state. The data sample corresponds to an integrated luminosity of 194 pb-1 collected with the CDF II detector from p over(p, ̄) collisions at a center of mass energy of 1.96 TeV. We observe two events with an expected signal of 1.0 ± 0.2 events and a background of 1.3 ± 0.3 events. We determine a 95% confidence level upper limit on rτ, the ratio of the measured rate of t → τ ν q to the expectation, of 5.2. © 2006 Elsevier B.V. All rights reserved.

Discovery of twin kHz QPOs in the peculiar X-ray binary Circinus X-1

(2006)

Authors:

S Boutloukos, M van der Klis, D Altamirano, M Klein-Wolt, R Wijnands, PG Jonker, RP Fender