Guy Wilkinson: Publications

Observation of charge-ordering in particle production in hadronic Z⁰ decay

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 407:2 (1997) 174-184

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, M Barbi, G Barbiellini, 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, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, C Bricman, RCA Brown, P Bruckman, JM Brunei, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, A Camacho Rozas, T Camporesi, V Canale, M Canepa, F Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, V Cindro, P Collins, R Contri

Abstract:

Analysis of the rapidity structure of charge correlations in hadronic events from Z0 decays gives evidence for chain-like charge-ordering of particle production along the thrust axis, as predicted by 'QCD-motivated string-like fragmentation models. © 1997 Published by Elsevier Science B.V.

Measurement of the spin density matrix for the ρ0, K*0(892) and φ produced in Z0 decays

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 406:3 (1997) 271-286

Authors:

P Abreu, W Adam, T Adye, 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, M Barbi, G Barbiellini, 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, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TV Bowcock, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, C Bricman, RCA Brown, P Bruckman, JM Brunet, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, A Camacho Rozas, T Camporesi, V Canale, M Canepa, F Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, M Chapkin, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, Y Chorowicz, J Chudoba, V Cindro, PP Collins, R Contri

Abstract:

The spin density matrix elements for the ρ⁰, K*⁰(892) and φ produced in hadronic Z⁰ decays are measured in the DELPHI detector. There is no evidence for spin alignment of the K*⁰(892) and φ in the region xp ≤ 0.3 (xp = p/pbeam), where ρ00 = 0.33 ± 0.05 and ρ00 = 0.30 ± 0.04, respectively. In the fragmentation region, xp ≥ 0.4, there is some indication for spin alignment of the ρ⁰ and K*⁰(892), since ρ00 = 0.43 ± 0.05 and ρ00 = 0.46 ± 0.08, respectively. These values are compared with those found in meson-induced hadronic reactions. For the φ, ρ00 = 0.30 ± 0.04 for xp ≥ 0.4 and 0.55 ± 0.10 for xp ≥ 0.7. The off-diagonal spin density matrix element ρ1 - 1 is consistent with zero in all cases.© 1997 Published by Elsevier Science B.V.

Measurement of the multiplicity of gluons splitting to bottom quark pairs in hadronic Z0 decays

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 405:1-2 (1997) 202-214

Authors:

P Abreu, W Adam, T Adye, I Ajinenko, GD Alekseev, R Alemany, U Amaldi, S Amato, P Andersson, A Andreazza, P Antilogus, WD Apel, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, M Barbi, G Barbiellini, DY Bardin, G Barker, A Baroncelli, O Barring, MJ Bates, M Battaglia, M Baubillier, J Baudot, KH Becks, M Begalli, P Beilliere, Y Belokopytov, K Belous, AC Benvenuti, 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, PSL Booth, AW Borgland, G Borisov, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, C Bricman, RCA 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 Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, P Charpentier, L Chaussard, P Cbecchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, V Cindro, P Collins, R Contri, E Cortina, G Cosme, F Cossutti, JH Cowell

Abstract:

An inclusive measurement of the average multiplicity of ��̄ pairs from gluons, g��̄, in hadronic Z⁰ events collected by the DELPHI experiment at LEP, is presented. A counting technique, based on jet b-tagging in 4-jet events, has been used. Looking for secondary bottom production in events with production of any primary flavour, by requiring two b-tagged jets in well defined topological configurations, gave g��̄ = (0.21 ± 0.11(stat) ± 0.09(syst))%. This result was checked with a different method designed to select events with four b quarks in the final state. Agreement within the errors was found.© 1997 Elsevier Science B.V.

Measurement of the transverse spin correlation in Z → τ+ τ- decays

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 404:1-2 (1997) 194-206

Authors:

E Abreu, W Adam, T Adye, I Ajinenko, GD Alekseev, R Alemany, PP Allport, S Almehed, U Amaldi, S Amato, P Andersson, A Andreazza, P Antilogus, WD Apel, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, E Barao, M Barbi, DY Bardin, G Barker, A Baroncelli, O Barring, MJ Bates, M Battaglia, M Baubillier, J Baudot, KH Becks, M Begalli, P Beilliere, Y Belokopytov, K Belous, AC Benvenuti, 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, 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, C Bricman, RCA 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, E Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, V Cindro, P Collins, R Contri, E Cortina, G Cosme

Abstract:

The measurement of the correlation between the transverse spin components of τ⁺ τ^- pairs collected during 1992 to 1994 with the DELPHI detector at LEP1 is presented. A value CTT = 0.87 ± 0.20 (stat.) +^0.10-0.12 (syst.) was obtained for the correlation parameter, in agreement with the Standard Model expectation. © 1997 Published by Elsevier Science B.V.

Identified particles in quark and gluon jets

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 401:1-2 (1997) 118-130

Authors:

P Abreu, W Adam, T Adye, I Ajinenko, GD Alekseev, R Alemany, PP Allport, S Almehed, U Amaldi, S Amato, A Andreazza, ML Andrieux, P Antilogus, WD Apel, B Åsman, JE Augustin, A Augustinus, P Baillon, P Bambade, F Barao, M Barbi, G Barbiellini, DY Bardin, G Barker, A Baroncelli, O Barring, JA Barrio, W Bartl, M Bates, M Battaglia, M Baubillier, J Baudot, KH Becks, M Begalli, P Beilliere, Y Belokopytov, AC Benvenuti, M Berggren, D Bertini, D Bertrand, M Besancon, F Bianchi, M Bigi, MS Bilenky, P Billoir, MA Bizouard, D Bloch, M Blume, T Bolognese, M Bonesini, W Bonivento, PSL Booth, C Bosio, O Botner, E Boudinov, B Bouquet, C Bourdarios, TJV Bowcock, M Bozzo, P Branchini, KD Brand, T Brenke, RA Brenner, C Bricman, RCA Brown, P Bruckman, JM Brunei, L Bugge, T Buran, T Burgsmueller, P Buschmann, S Cabrera, M Caccia, M Calvi, AJ Camacho Rozas, T Camporesi, V Canale, M Canepa, K Cankocak, F Cao, F Carena, L Carroll, C Caso, MV Castillo Gimenez, A Cattai, FR Cavallo, V Chabaud, P Charpentier, L Chaussard, P Checchia, GA Chelkov, M Chen, R Chierici, P Chliapnikov, P Chochula, V Chorowicz, J Chudoba, V Cindro, P Collins, R Contri

Abstract:

A sample of about 1.4 million hadronic Z decays, selected among the data recorded by the DELPHI detector at LEP during 1994, was used to measure for the first time the momentum spectra of K+, K0, p, Λ and their antiparticles in gluon and quark jets. As observed for inclusive charged particles, the production spectra of identified particles were found to be softer in gluon jets than in quark jets, with a higher total multiplicity. © 1997 Published by Elsevier Science B.V.

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Guy Wilkinson

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Observation of charge-ordering in particle production in hadronic Z⁰ decay

Authors:

Abstract:

Measurement of the spin density matrix for the ρ0, K*0(892) and φ produced in Z0 decays

Authors:

Abstract:

Measurement of the multiplicity of gluons splitting to bottom quark pairs in hadronic Z0 decays

Authors:

Abstract:

Measurement of the transverse spin correlation in Z → τ+ τ- decays

Authors:

Abstract:

Identified particles in quark and gluon jets

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Abstract:

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Guy Wilkinson

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Observation of charge-ordering in particle production in hadronic Z0 decay

Authors:

Abstract:

Measurement of the spin density matrix for the ρ0, K*0(892) and φ produced in Z0 decays

Authors:

Abstract:

Measurement of the multiplicity of gluons splitting to bottom quark pairs in hadronic Z0 decays

Authors:

Abstract:

Measurement of the transverse spin correlation in Z → τ+ τ- decays

Authors:

Abstract:

Identified particles in quark and gluon jets

Authors:

Abstract:

Observation of charge-ordering in particle production in hadronic Z⁰ decay