The observation of a new b baryon via its strong decay into Xi(-)(b)pi(+) (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at root s = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 fb(-1). The known Xi(-)(b) baryon is reconstructed via the decay chain Xi(-)(b) -> J/psi Xi(-) -> mu(+)mu(-)Lambda(0)pi(-), with Lambda(0) -> p pi(-). A peak is observed in the distribution of the difference between the mass of the Xi(-)(b)pi(+) system and the sum of the masses of the Xi(-)(b) and pi(+), with a significance exceeding 5 standard deviations. The mass difference of the peak is 14.84 +/- 0.74(stat) +/- 0.28(syst) MeV. The new state most likely corresponds to the J(P) = 3/2(+) companion of the Xi(b).

Observation of a New Xi(b) Baryon / Chatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Aguilo, E., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V.M., Hammer, J., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 108:25(2012). [10.1103/PhysRevLett.108.252002]

Observation of a New Xi(b) Baryon

D. Creanza;N. De Filippis;G. Iaselli;G. Maggi;G. Pugliese;
2012

Abstract

The observation of a new b baryon via its strong decay into Xi(-)(b)pi(+) (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at root s = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 fb(-1). The known Xi(-)(b) baryon is reconstructed via the decay chain Xi(-)(b) -> J/psi Xi(-) -> mu(+)mu(-)Lambda(0)pi(-), with Lambda(0) -> p pi(-). A peak is observed in the distribution of the difference between the mass of the Xi(-)(b)pi(+) system and the sum of the masses of the Xi(-)(b) and pi(+), with a significance exceeding 5 standard deviations. The mass difference of the peak is 14.84 +/- 0.74(stat) +/- 0.28(syst) MeV. The new state most likely corresponds to the J(P) = 3/2(+) companion of the Xi(b).
2012
Observation of a New Xi(b) Baryon / Chatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Aguilo, E., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V.M., Hammer, J., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 108:25(2012). [10.1103/PhysRevLett.108.252002]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/8133
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