Measurement of the charged multiplicity of bottom and light quark events in e+e− annihilation at GeV

Okabe, K.; Yamada, Y.; Tatsumi, Daisuke; Abe, K.; Amako, K.; Arai, Y.; Asano, Y.; Chiba, M.; Chiba, Yasuo; Daigo, M.; Fukawa, M.; Fukushima, Y.; Haba, J.; Hamasaki, Hiroshi; Hemmi, Y.; Higuchi, M.; Hirose, T.; Homma, Y.; Ishihara, N.; Iwata, Y.; Kanzaki, J.; Kikuchi, R.; Kondo, T.; Korhonen, T.; Kurashige, H.; Matsuda, E. K.; Matsui, Takayuki; Miyake, K.; Mori, Shigeki; Nagashima, Y.; Nakagawa, Y.; Nakamura, T.; Nakano, I.; Ogawa, K.; Ohama, T.; Ohsugi, T.; Ohyama, H.; Okamoto, Atsushi; Ono, A.; Pennanen, J.; Sakamoto, H.; Sakuda, M.; Sato, Minoru; Sato, Nobuaki; Shioden, M.; Shirai, J.; Sumiyoshi, T.; Takada, Yoshihisa; Takasaki, F.; Takita, M.; Tamura, N.; Tobimatsu, K.; Tsuboyama, T.; Uehara, S.; Unno, Y.; Watanabe, Toru; Watase, Y.; Yabuki, F.; Yamagata, T.; Yonezawa, Yasushige; Yoshida, Hajime; Yusa, K.

doi:10.1016/s0370-2693(98)00073-2

Cited by 8 publications

(11 citation statements)

References 22 publications

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“…energies √ s ≡ W from PEP, at √ s = 29 GeV, to LEP2 at √ s = 206 GeV [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. For reviews on this topic see, for instance, [46][47][48].…”

Section: Discussion and Estimate Of Next-to-mlla Terms Of The Order Omentioning

confidence: 99%

“…(12). This figure is taken from [44] with the addition of the result from the VENUS experiment at √ s = 58 GeV [36] as well as the preliminary result from DELPHI at √ s = 206 GeV [49] . The dash-dotted line shown in Fig.…”

Section: Discussion and Estimate Of Next-to-mlla Terms Of The Order Omentioning

confidence: 99%

“…We considered only published results obtained in the continuum, thus away from the J/Ψ and Υ resonances, which were determined following what is now considered a standard convention [57], namely including in the evaluation of the mean value all charged particles produced in the decays of particles with lifetimes shorter than 3 · 10 −10 sec. [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74]. This means that the charged decay products of K 0 s and of weakly decaying heavy-mesons (D,B, .…”

Section: Test Of Mlla Predictions For B Quark Jetsmentioning

confidence: 99%

“…The other experiments, instead, have only measured N ch b and N ch had , and, thus, one particular value for N ch c or δ cℓ must be assumed in order to evaluate N ch ℓ and δ bℓ . In the previous reviews, the value of δ cℓ was the same as in [15], while in the recent publication by VENUS [36] the result of OPAL measurement [38] is taken. In Table 2 we used for all these experiments the new average value of δ cℓ presented in the previous section, δ cℓ = 1.0 ± 0.4, and this explains why these results are not the same as those presented in previous publications.…”

Section: B2 About the Measurement Of δ Bℓmentioning

confidence: 99%

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Multiplicity Difference between Heavy and Light Quark Jets Revisited

Fabbri¹

2006

AIP Conference Proceedings

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The perturbative QCD approach to multiparticle production predicts a characteristic suppression of particle multiplicity in a heavy quark jet as compared to a light quark jet. In the Modified Leading Logarithmic Approximation (MLLA) the multiplicity difference δ Qℓ between heavy and light quark jets is derived in terms of a few other experimentally measured quantities. The earlier prediction for b-quarks needs revision in the light of new experimental results and the improvement in the understanding of the experimental data. We now find δ bℓ = 4.4 ± 0.4. The updated MLLA results on δ bℓ and δ cℓ are compared with the present data from e + e − annihilation. Their expected energy independence is confirmed within the energy range between 29 and 200 GeV; the absolute values are now in better agreement with experiment than in the previous analysis, and the remaining difference can be attributed largely to next-to-MLLA contributions, an important subset of which are identified and evaluated.

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Section: Discussion and Estimate Of Next-to-mlla Terms Of The Order Omentioning

confidence: 99%

Section: Discussion and Estimate Of Next-to-mlla Terms Of The Order Omentioning

confidence: 99%

Section: Test Of Mlla Predictions For B Quark Jetsmentioning

confidence: 99%

Section: B2 About the Measurement Of δ Bℓmentioning

confidence: 99%

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Multiplicity Difference between Heavy and Light Quark Jets Revisited

Fabbri¹

2006

AIP Conference Proceedings

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“…The reason is simple: massive particles decay, and the same angular scale m=E appears both in the dead cone effect as well as in the characteristic opening angle between the decay products. In this way, the dead cone is effectively "filled," so, while the overall suppression of gluon radiation for heavy quarks can be inferred through inclusive [4][5][6][7][8] or semi-inclusive [9][10][11] observables, the universal angular radiation pattern around the massive particle is obscured. More direct probes of the dead cone for bottom and charm quarks have been put forward, for example in e þ e − collisions at LEP [12,13] and in ep collisions at HERA [14], and the dead cone effect is included in the shower deconstruction approach to top tagging [15].…”

Section: Introductionmentioning

confidence: 99%

Exposing the dead cone effect with jet substructure techniques

2016

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The dead cone is a well-known effect in gauge theories, where radiation from a charged particle of mass m and energy E is suppressed within an angular size of m=E. This effect is universal as it does not depend on the spin of the particle nor on the nature of the gauge interaction. It is challenging to directly measure the dead cone at colliders, however, since the region of suppressed radiation either is too small to be resolved or is filled by the decay products of the massive particle. In this paper, we propose to use jet substructure techniques to expose the dead cone effect in the strong-force radiation pattern around boosted top quarks at the Large Hadron Collider. Our study shows that with 300=fb of 13-14 TeV collision data, ATLAS and CMS could obtain the first direct evidence of the dead cone effect and test its basic features.

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