Accelerator Neutrinos

Research group

Research theme

Sub department

About

Related research groups

Measurement of the top quark mass using template methods on dilepton events in pp̄ collisions at s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 73:11 (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, 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, CI Ciobanu

Abstract:

We describe a measurement of the top quark mass from events produced in pp̄ collisions at a center-of-mass energy of 1.96 TeV, using the Collider Detector at Fermilab. We identify tt̄ candidates where both W bosons from the top quarks decay into leptons (eν, μν, or τν) from a data sample of 360pb-1. The top quark mass is reconstructed in each event separately by three different methods, which draw upon simulated distributions of the neutrino pseudorapidity, tt̄ longitudinal momentum, or neutrino azimuthal angle in order to extract probability distributions for the top quark mass. For each method, representative mass distributions, or templates, are constructed from simulated samples of signal and background events, and parametrized to form continuous probability density functions. A likelihood fit incorporating these parametrized templates is then performed on the data sample masses in order to derive a final top quark mass. Combining the three template methods, taking into account correlations in their statistical and systematic uncertainties, results in a top quark mass measurement of 170.1±6.0(stat.)±4.1(syst.) GeV/c2. © 2006 The American Physical Society.
More details from the publisher

Measurement of the helicity of W bosons in top-quark decays

Physical Review D - Particles, Fields, Gravitation and Cosmology 73:11 (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, 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 measure the branching fraction of the top quark to longitudinally and right-handed polarized W bosons, F0 and F+, using approximately 200pb-1 of p̄p collisions collected by the CDF II detector. We analyze two quantities sensitive to the W helicity: the invariant mass of the charged lepton and the bottom-quark jet in the decay t→Wb→ νb (where =e or μ), and the transverse momentum of the charged lepton. Constrained fits yield F0=0.74-0.34+0.22, and F+<0.27 at the 95% confidence level. These measurements are consistent with the standard model predictions. © 2006 The American Physical Society.
More details from the publisher

Observation of Bs0→ψ(2S) and measurement of the ratio of branching fractions B(Bs0→ψ(2S) /B(Bs0→J/ψ)

Physical Review Letters 96:23 (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, 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, CI Ciobanu

Abstract:

We report the first observation of Bs0→ψ(2S) decay in pp̄ collisions at s= 1.96 TeV using 360 pb-1 of data collected by the CDF II detector at the Fermilab Tevatron. We observe 20.2±5.0 and 12.3±4.1 Bs0→ψ(2S) candidates, in ψ(2S)→μ+μ- and ψ(2S)→J/ψπ+π- decay modes, respectively. We present a measurement of the relative branching fraction B(Bs0→ψ(2S) /B(Bs0→J/ψ)=0.52±0.13(stat)±0.04(syst)±0.06(BR) using the ψ(2S)→μ+μ- decay mode. © 2006 The American Physical Society.
More details from the publisher

Charged Pion Production in p+C Collisions at 158 GeV/c Beam Momentum: Discussion

(2006)

Authors:

G Barr, O Chvala, HG Fischer, M Kreps, M Makariev, C Pattison, A Rybicki, D Varga, S Wenig
More details from the publisher

Search for excited muons in pp̄ collisions at s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 73:11 (2006)

Authors:

VM Abazov, B Abbott, M Abolins, BS Acharya, M Adams, T Adams, M Agelou, JL Agram, SH Ahn, M Ahsan, GD Alexeev, G Alkhazov, A Alton, G Alverson, GA Alves, M Anastasoaie, T Andeen, S Anderson, B Andrieu, MS Anzelc, Y Arnoud, M Arov, A Askew, B Åsman, ACSA Jesus, O Atramentov, C Autermann, C Avila, C Ay, F Badaud, A Baden, L Bagby, B Baldin, DV Bandurin, P Banerjee, S Banerjee, E Barberis, P Bargassa, P Baringer, C Barnes, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, M Begalli, M Begel, C Belanger-Champagne, A Bellavance, JA Benitez, SB Beri, G Bernardi, R Bernhard, L Berntzon, I Bertram, M Besançon, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Binder, C Biscarat, KM Black, I Blackler, G Blazey, F Blekman, S Blessing, D Bloch, K Bloom, U Blumenschein, A Boehnlein, O Boeriu, TA Bolton, F Borcherding, G Borissov, K Bos, T Bose, A Brandt, R Brock, G Brooijmans, A Bross, D Brown, NJ Buchanan, D Buchholz, M Buehler, V Buescher, S Burdin, S Burke, TH Burnett, E Busato, CP Buszello, JM Butler, S Calvet, J Cammin, S Caron, W Carvalho, BCK Casey, NM Cason, H Castilla-Valdez, S Chakrabarti

Abstract:

We present the results of a search for the production of an excited state of the muon, μ*, in proton antiproton collisions at s=1.96TeV. The data have been collected with the D0 experiment at the Fermilab Tevatron Collider and correspond to an integrated luminosity of approximately 380pb-1. We search for μ* in the process pp̄→μ*μ, with the μ* subsequently decaying to a muon plus photon. No excess above the standard model expectation is observed in data. Interpreting our data in the context of a model that describes μ* production by four-fermion contact interactions and μ* decay via electroweak processes, we set a 95% confidence level production cross section upper limit ranging from 0.057 to 0.112 pb, depending on the mass of the excited muon. Choosing the scale for contact interactions to be Λ=1TeV, excited muon masses below 618 GeV are excluded. © 2006 The American Physical Society.
More details from the publisher