Measurement of the fraction of \Y1S originating from \chib1P decays in $pp$ collisions at $\sqrt{s} = 7\tev

• Published in: The journal of high energy physics 2012, Vol.11
• Main Authors: Aaij, R., Barsuk, S., Callot, O., He, J., Jean-Marie, B., Lefrançois, J., Machefert, F., Martin Sanchez, A., Nicol, M., Robbe, P., Schune, M.-H., Viaud, B., Videau, I., Ben-Haim, E., Benayoun, M., David, P., del Buono, L., Martens, A., de Bonis, I., Decamp, D., Ghez, Ph, Hopchev, P., Lees, J.-P., Machikhiliyan, I.V., Minard, M.-N., Pietrzyk, B., t'Jampens, S., Tisserand, V., Tournefier, E., Adrover, C., Aslanides, E., Cogan, J., Khanji, B., Le Gac, R., Leroy, O., Mancinelli, G., Maurice, E., Perrin-Terrin, M., Sapunov, M., Serrano, J., Tsaregorodtsev, A., Ajaltouni, Ziad Zj, Cogneras, E., Deschamps, O., El Rifai, I., Henrard, Pierre, Hoballah, M., Jahjah-Hussein, Marwa, Lefèvre, R., Li Gioi, L., Monteil, S., Niess, V., Perret, Pascal, Roa Romero, Diego Alejandro, Sobczak, Krzysztof Grzegorz
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 1126-6708; 1029-8479
• DOI: 10.1007/JHEP11(2012)031

The production of \chib1P mesons in $pp$ collisions at a centre-of-mass energy of $7\tev$ is studied using $32\invpb$ of data collected with the \lhcb detector. The $\chib1P$ mesons are reconstructed in the decay mode $\chib1P \to \Y1S\g \to \mumu\g$. The fraction of \Y1S originating from \chib1P decays in the \Y1S transverse momentum range $6 < \pt^{\Y1S} < 15\gevc$ and rapidity range $2.0 < y^{\Y1S} < 4.5$ is measured to be $(20.7\pm 5.7\pm 2.1^{+2.7}_{-5.4})%$, where the first uncertainty is statistical, the second is systematic and the last gives the range of the result due to the unknown \Y1S and \chib1P polarizations.