LHCb

Research group

Sub department

About

Measurement of the inclusive charmless and double-charm B branching ratios

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 426:1-2 (1998) 193-206

Authors:

P Abreu, W Adam, T Adye, P Adzic, GD Alekseev, R Alemany, PP Allport, S Almehed, U Amaldi, S Amato, P Andersson, A Andreazza, P Antilogus, WD Apel, Y Arnoud, B Ã…sman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barbier, DY Bardin, G Barker, A Baroncelli, O Barring, MJ Bates, M Battaglia, M Baubillier, KH Becks, M Begalli, P Beilliere, Y Belokopytov, K Belous, AC Benvenuti, C Berat, M Berggren, D Bertini, D Bertrand, M Besancon, F Bianchi, M Bigi, MS Bilenky, P Billoir, MA Bizouard, D Bloch, M Bonesini, W Bonivento, M Boonekamp, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, I Bozovic, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, R Brown, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, C Cerruti, V Chabaud, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, P Collins, M Colomer, R Contri

Abstract:

The DELPHI experiment at LEP has measured the inclusive charmless B hadron decay branching ratio, the B branching ratio into two charmed particles, and the total number of charmed particles per B decay, using the hadronic Z data taken between 1992 and 1995. The results are extracted from a fit to the b-tagging probability distribution based on the precise impact parameter measurements made using the microvertex detector. The inclusive charmless B branching ratio, including B decays into hidden charm (cc̄), is measured to be 0.033 ± 0.021. The B branching ratio into two open charmed particles is 0.136 ± 0.042. The mean number of charmed particles per B decay (including hidden charm) is 1.147 ± 0.041. After subtracting the B decay branching ratio into hidden charm, the charmless B branching ratio is found to be 0.007 ± 0.021, compatible with the Standard Model expectation. Models that predict an additional contribution to the charmless B branching ratio of 0.037 or higher are excluded with at least 95% confidence. © 1998 Elsevier Science B.V. All rights reserved.

Measurement of the charged particle multiplicity of weakly decaying B hadrons

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 425:3-4 (1998) 399-412

Authors:

P Abreu, W Adam, T Adye, P Adzic, I Ajinenko, GD Alekseev, R Alemany, PP Allport, S Almehed, U Amaldi, S Amato, P Andersson, A Andreazz, P Antilogus, WD Apel, Y Arnoud, B Asman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barbier, DY Bardin, G Barker, A Baroncelli, O Barring, M Battaglia, M Baubillier, KH Becks, M Begalli, P Beilliere, Y Belokopytov, AC Benvenuti, C Berat, M Berggren, D Bertini, D Bertrand, M Besancon, F Bianchi, M Bigi, MS Bilenky, MA Bizouard, D Bloch, M Bonesini, W Bonivento, M Boonekamp, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, I Boyko, I Bozovic, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, R Brown, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, C Cerruti, V Chabaud, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, P Collins, M Colomer, R Contri, E Cortina

Abstract:

From the Z decays recorded in 1994 and 1995 by the DELPHI detector at LEP, the charged particle multiplicity of weakly decaying B hadrons was measured to be: 4.97 ± 0.03 ± 0.06 excluding the K o and A decay products. © 1998 Published by Elsevier Science B.V. All rights reserved.

Measurement of trilinear gauge couplings in e+e- collisions at 161 GeV and 172 GeV

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 423:1-2 (1998) 194-206

Authors:

P Abreu, W Adam, T Adye, P Adzic, GD Alekseev, R Alemany, PP Allport, S Almehed, U Amaldi, S Amato, P Andersson, A Andreazza, P Antilogus, WD Apel, Y Arnoud, B Ã…sman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barbier, DY Bardin, G Barker, A Baroncelli, O Barring, MJ Bates, M Battaglia, M Baubillier, KH Becks, M Begalli, P Beilliere, Y Belokopytov, AC Benvenuti, C Berat, M Berggren, D Bertini, D Bertrand, M Besancon, F Bianchi, M Bigi, MS Bilenky, P Billoir, MA Bizouard, D Bloch, M Bonesini, W Bonivento, M Boonekamp, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, I Bozovic, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, R Brown, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, C Cerruti, V Chabaud, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, P Collins, M Colomer, R Contri, E Cortina

Abstract:

Trilinear gauge boson couplings are measured using data taken by DELPHI at 161 GeV and 172 GeV. Values for WWV couplings (V = Z,γ) are determined from a study of the reactions e+e-→ W+W- and e+e- → Wev, using differential distributions from the WW final state in which one W decays hadronically and the other leptonically, and total cross-section data from other channels. Limits are also derived on neutral ZVγ couplings from an analysis of the reaction e+e-→ y + invisible particles. © 1998 Elsevier Science B.V.

Event shape analysis of deep inelastic scattering events with a large rapidity gap at HERA

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 421:1-4 (1998) 368-384

Authors:

J Breitweg, M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, J Repond, R Stanek, RL Talaga, R Yoshida, H Zhang, MCK Mattingly, F Anselmo, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, G Cara Romeo, G Castellini, L Cifarelli, F Cindolo, A Contin, M Corradi, S de Pasquale, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, F Palmonari, A Pesci, A Polini, F Ricci, G Sartorelli, Y Zamora Garcia, A Zichichi, C Amelung, A Bornheim, I Brock, K Coböken, J Crittenden, R Deffner, M Eckert, M Grothe, H Hartmann, K Heinloth, L Heinz, E Hilger, HP Jakob, UF Katz, R Kerger, E Paul, M Pfeiffer, C Rembser, J Stamm, R Wedemeyer, H Wieber, DS Bailey, S Campbell-Robson, WN Cottingham, B Foster, R Hall-Wilton, ME Hayes, GP Heath, HF Heath, JD McFall, D Piccioni, DG Roff, RJ Tapper, M Arneodo, R Ayad, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, JY Kim, JH Lee, IT Lim, MY Pac, A Caldwell, N Cartiglia, Z Jing, W Liu, B Mellado, JA Parsons, S Ritz, S Sampson, F Sciulli, PB Straub, Q Zhu, P Borzemski, J Chwastowski, A Eskreys

Abstract:

A global event shape analysis of the multihadronic final states observed in neutral current deep inelastic scattering events with a large rapidity gap with respect to the proton direction is presented. The analysis is performed in the range 5 ≤ Q2 ≤ 185 GeV2 and 160 ≤ W ≤ 250 GeV, where Q2 is the virtuality of the photon and W is the virtual-photon proton centre of mass energy. Particular emphasis is placed on the dependence of the shape variables, measured in the γ * -pomeron rest frame, on the mass of the hadronic final state, MX. With increasing MX the multihadronic final state becomes more collimated and planar. The experimental results are compared with several models which attempt to describe diffractive events. The broadening effects exhibited by the data require in these models a significant gluon component of the pomeron. © 1998 Elsevier Science B.V.

Search for charged Higgs bosons in e+e- collisions at √s = 172 GeV

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 420:1-2 (1998) 140-156

Authors:

P Abreu, W Adam, T Adye, P Adzic, GD Alekseev, R Alemany, PP Allport, S Almehed, U Amaldi, S Amato, P Andersson, A Andreazza, P Antilogus, WD Apel, Y Arnoud, B Ã…sman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, R Barbier, DY Bardin, G Barker, A Baroncelli, O Barring, MJ Bates, M Battaglia, M Baubillier, J Baudot, KH Becks, M Begalli, P Beilliere, Y Belokopytov, AC Benvenuti, C Berat, M Berggren, D Bertini, D Bertrand, M Besancon, F Bianchi, M Bigi, MS Bilenky, P Billoir, MA Bizouard, D Bloch, M Blume, M Bonesini, W Bonivento, M Boonekamp, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, I Bozovic, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, R Brown, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, C Cerruti, V Chabaud, N Chalanda, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, V Cindro

Abstract:

This paper presents results on charged Higgs boson production, based on LEP data collected at √s = 172 GeV, that complement the previous DELPHI results obtained at centre of mass energies up to 161 GeV. The charged Higgs bosons are assumed to be pair produced and to decay either into a quark pair or into τVτ. The three different possible final states are included in the analysis. Data from ring imaging Cherenkov and microvertex detectors are used to identify the quarks as a cs pair. The number of candidates found is compatible with the background expected from standard processes. Combining the results of the present analysis with those of the previous analysis at lower energies, a new lower mass limit for the charged Higgs boson is set at 54.5 GeV/c2. © 1998 Elsevier Science B.V.