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A study of the hadronic resonance structure in the decay τ → 3πντ

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 426:3-4 (1998) 411-427

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 Asman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, G Barbiellini, 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, 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, K Cieslik, P Collins

Abstract:

The hadronic structure of the decay of the τ lepton to three charged particles, τ → 3πντ, is studied using data collected by the DELPHI detector at LEP between 1992 and 1995. The invariant mass of the 3π system, m3π, is fitted using the models of Kühn and Santamaria, Isgur Morningstar and Reader, and Feindt. The 3π and π+π- mass spectra are compared with each model. Below m23π = 2.3 GeV2, all are in good qualitative agreement. Above m23π = 2.3 GeV2, anomalous behaviour is observed, consistent with the existence of a hitherto unseen decay mode of the τ through a radial excitation of the a1 meson. © 1998 Published by Elsevier Science B.V. All rights reserved.
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The physics performance of LHCb

NUCL INSTRUM METH A 408:1 (1998) 137-145

Authors:

N Harnew, LHCb Collaboration

Abstract:

The LHCb experiment is based on a single arm forward spectrometer optimized to study CP violation in the B system at the LHC. The experiment includes a dedicated trigger system, particle identification and a precise vertex determination; recent developments in these areas will be summarized. The detector will provide precise measurements of all angles of the unitarity triangle, the length of one of the sides (via B-s(0) - (B) over bar(s)(0) mixing) and the height of the triangle. The physics performance for selected channels will be reviewed. (C) 1998 Elsevier Science B.V. All rights reserved.
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First evidence for a charm radial excitation, D

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 426:1-2 (1998) 231-242

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 Andreazza, P Antilogus, WD Apel, Y Arnoud, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, G Barbiellini, 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, 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:

Using D *+ mesons exclusively reconstructed in the DELPHI detector at LEP, an excess of 66 ± 14(stat.) events is observed in the D *+π+ π- final state with a mass of 2637 ± 2(stat.) ± 6(syst.) MeV/c2 and a full width smaller than 15 MeV/c2 (95% C.L.). This signal is compatible with the expected decay of a radially excited D *′ (JP = 1-) meson. © 1998 Published by Elsevier Science B.V. All rights reserved.
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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 Åsman, 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.
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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.
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