SNO+

Research group

Research theme

Sub department

About

Measurement of b quark fragmentation fractions in the production of strange and light B mesons in pp̄ collisions at √s=1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 60:9 (1999) 1-14

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, P Azzi-Bacchetta, N Bacchetta, S Bagdasarov, MW Bailey, P De Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, S Bertolucci, S Bettelli, B Bevensee, A Bhatti, K Biery, C Bigongiari, M Binkley, D Bisello, RE Blair, C Blocker, K Bloom, S Blusk, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, L Breccia, C Bromberg, N Bruner, R Brunetti, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, A Caner, W Carithers, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, M Chertok, G Chiarelli, CN Chiou, F Chlebana, L Christofek, ML Chu, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, D Costanzo, C Couyoumtzelis, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart, T Daniels, F DeJongh, S Dell'Agnello, M Dell'Orso

Abstract:

A new technique to measure the ratio of b quark fragmentation fractions in pp̄ collisions is described. Using a 70-pb-1 sample of low-mass dimuon trigger data recorded with the Collider Detector at Fermilab, we identify B mesons by observing the double semileptonic decays b→c μX with c→s μX. By counting the numbers of K*(892)0, K*(892)+, and φ(1020) mesons produced in association with these muon pairs, we measure the ratio of strange to nonstrange B meson production to be fs/(fu+fd)=[21.0±3.6(stat) -3.0+3.8(syst)]%. This measurement is the most precise available from hadron collisions to date. Limits on the branching fractions of semileptonic charm meson decays with K1(1270), K1* (1410), and K2*(1430) mesons in the final state are also obtained. ©1999 The American Physical Society.

Measurement of the associated γ+μ± production cross section in pp̄ collisions at √s=1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 60:9 (1999) 1-5

Authors:

F Abe, MG Albrow, SR Amendolia, D Amidei, J Antos, C Anway-Wiese, G Apollinari, H Areti, M Atac, P Auchincloss, F Azfar, P Azzi, N Bacchetta, W Badgett, MW Bailey, J Bao, P De Barbara, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Bartalini, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettin, J Bellinger, D Benjamin, J Benlloch, J Bensinger, D Benton, A Beretvas, JP Berge, S Bertolucci, A Bhatti, K Biery, M Binkley, F Bird, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, D Bortoletto, C Boswell, T Boulos, G Brandenburg, C Bromberg, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, J Cammerata, C Campagnari, M Campbell, A Caner, W Carithers, D Carlsmith, A Castro, Y Cen, F Cervelli, HY Chao, J Chapman, MT Cheng, G Chiarelli, T Chikamatsu, CN Chiou, L Christofek, S Cihangir, AG Clark, M Cobal, M Contreras, J Conway, J Cooper, M Cordelli, C Couyoumtzelis, D Crane, JD Cunningham, T Daniels, F DeJongh, S Delchamps, S Dell'Agnello, M Dell'Orso, L Demortier, B Denby, M Deninno, PF Derwent, T Devlin, M Dickson, JR Dittmann, S Donati, RB Drucker, A Dunn, K Einsweiler, JE Elias, R Ely

Abstract:

We present the first measurement of associated direct photon+muon production in hadronic collisions, from a sample of 1.8 TeV pp collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily from the Compton scattering process cg→cγ, with the final state charm quark producing a muon. Hence this measurement is sensitive to the charm quark content of the proton. The measured cross section of 29±9 pb is compared to a leading-order QCD parton shower model as well as a next-to-leading-order QCD calculation. ©1999 The American Physical Society.
More details from the publisher

Measurement of B0-B̄0 flavor oscillations using jet-charge and lepton flavor tagging in pp̄ collisions at √s=1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 60:7 (1999) 1-22

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, P Azzi-Bacchetta, N Bacchetta, S Bagdasarov, MW Bailey, P De Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, S Bertolucci, S Bettelli, B Bevensee, A Bhatti, K Biery, C Bigongiari, M Binkley, D Bisello, RE Blair, C Blocker, K Bloom, S Blusk, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, L Breccia, C Bromberg, N Bruner, R Brunetti, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, A Caner, W Carithers, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, M Chertok, G Chiarelli, CN Chiou, F Chlebana, L Christofek, ML Chu, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, D Costanzo, C Couyoumtzelis, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart, T Daniels, F DeJongh, S Dell'Agnello, M Dell'Orso

Abstract:

We present a measurement of the mass difference Δmd for the B0 meson and the statistical power of the b flavor tagging methods used. The measurement uses 90 pb-1 of data from pp̄ collisions at √s= 1.8 TeV collected with the CDF detector. An inclusive lepton trigger is used to collect a large sample of B hadron semileptonic decays. The mass difference Δmd is determined from the proper time dependence of the fraction of B hadrons that undergo flavor oscillations. The flavor at decay is inferred from the charge of the lepton from semileptonic B decay. The initial flavor is inferred by determining the flavor of the other B hadron produced in the collision, either from its semileptonic decay (soft-lepton tag) or from its jet charge. The measurement yields Δmd=(0.500±0.052±0.043)ℏ ps-1, where the first uncertainty is statistical and the second uncertainty is systematic. The statistical powers (∈D2) of the soft-lepton and jet-charge flavor taggers are (0.91±0.10 ±0.11)% and (0.78±0.12±0.08)%, respectively. ©1999 The American Physical Society.
More details from the publisher

Measurement of the Bd0B̄d0 oscillation frequency using dimuon data in pp̄ collisions at √s = 1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 60:5 (1999) 1-6

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, P Azzi-Bacchetta, N Bacchetta, S Bagdasarov, MW Bailey, P De Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, S Bertolucci, S Bettelli, B Bevensee, A Bhatti, K Biery, C Bigongiari, M Binkley, D Bisello, RE Blair, C Blocker, K Bloom, S Blusk, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, L Breccia, C Bromberg, N Bruner, R Brunetti, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, A Caner, W Carithers, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, M Chertok, G Chiarelli, CN Chiou, F Chlebana, L Christofek, ML Chu, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, D Costanzo, C Couyoumtzelis, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart, T Daniels, F DeJongh, S Dell'Agnello, M Dell'Orso

Abstract:

We present a measurement of the mass difference Δmd of the two Bd0 mass eigenstates. We use a flavor tagging method based on the lepton charge, in a sample of events with two muons at low transverse momentum. The sample corresponds to an integrated luminosity of 90 pb-1 collected by the Collider Detector at Fermilab. The result obtained is Δmd=0.503±0.064(stat)±0.071(syst) ps-1. ©1999 The American Physical Society.
More details from the publisher

Measurements of photomultiplier single photon counting efficiency for the Sudbury Neutrino Observatory

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 432:2-3 (1999) 364-373

Authors:

SD Biller, NA Jelley, MD Thorman, NP Fox, TH Ward

Abstract:

A knowledge of the absolute efficiency of the photomultiplier tubes (PMTs) used in the Sudbury Neutrino Observatory (SNO) is important for modelling the behaviour of the detector. While the quantum efficiencies for the PMTs are known, the efficiency in single-photon counting mode (which includes collection efficiency and counting efficiency) is of more relevance. A calibration of the 8 in. Hamamatsu R1408 photomultipliers in this mode requires a known flux of incident light at the very low level of 10-16 W cm-2 (250 photons cm-2 s-1). A method of performing such measurements, utilising the extreme linearity obtainable with silicon photodiodes, is presented in this paper. The results of efficiency measurements on four PMTs are given and a comparison is made with previous results obtained using a Cherenkov source of known intensity.
More details from the publisher
More details