Measurement of the Λb polarization and angular parameters in Λb →j /ψ Λ decays from pp collisions at s =7 and 8 TeV MEASUREMENT of the Λb POLARIZATION ⋯ A. M. SIRUNYAN et al.

Date Issued
01-04-2018
Author(s)
Sirunyan, A. M.
Tumasyan, A.
Adam, W.
Ambrogi, F.
Asilar, E.
Bergauer, T.
Brandstetter, J.
Brondolin, E.
Dragicevic, M.
Erö, J.
Escalante Del Valle, A.
Flechl, M.
Friedl, M.
Frühwirth, R.
Ghete, V. M.
Grossmann, J.
Hrubec, J.
Jeitler, M.
König, A.
Krammer, N.
Krätschmer, I.
Liko, D.
Madlener, T.
Mikulec, I.
Pree, E.
Rad, N.
Rohringer, H.
Schieck, J.
Schöfbeck, R.
Spanring, M.
Spitzbart, D.
Taurok, A.
Waltenberger, W.
Wittmann, J.
Wulz, C. E.
Zarucki, M.
Chekhovsky, V.
Mossolov, V.
Suarez Gonzalez, J.
De Wolf, E. A.
Di Croce, D.
Janssen, X.
Lauwers, J.
Van Haevermaet, H.
Van Mechelen, P.
Van Remortel, N.
Abu Zeid, S.
Blekman, F.
D'Hondt, J.
De Bruyn, I.
De Clercq, J.
Deroover, K.
Flouris, G.
Lontkovskyi, D.
Lowette, S.
Marchesini, I.
Moortgat, S.
Moreels, L.
Python, Q.
Skovpen, K.
Tavernier, S.
Van Doninck, W.
Van Mulders, P.
Van Parijs, I.
Beghin, D.
Bilin, B.
Brun, H.
Clerbaux, B.
De Lentdecker, G.
Delannoy, H.
Dorney, B.
Fasanella, G.
Favart, L.
Goldouzian, R.
Grebenyuk, A.
Kalsi, A. K.
Lenzi, T.
Luetic, J.
Maerschalk, T.
Marinov, A.
Seva, T.
Starling, E.
Vander Velde, C.
Vanlaer, P.
Vannerom, D.
Yonamine, R.
Zenoni, F.
Cornelis, T.
Dobur, D.
Fagot, A.
Gul, M.
Khvastunov, I.
Poyraz, D.
Roskas, C.
Salva, S.
Trocino, D.
Tytgat, M.
Verbeke, W.
Zaganidis, N.
Bakhshiansohi, H.
DOI
Abstract
An analysis of the bottom baryon decay Λb→J/ψ(→μ+μ-)Λ(→pπ-) is performed to measure the Λb polarization and three angular parameters in data from pp collisions at s=7 and 8 TeV, collected by the CMS experiment at the Large Hadron Collider. The Λb polarization is measured to be 0.00±0.06(stat)±0.06(syst) and the parity-violating asymmetry parameter is determined to be 0.14±0.14(stat)±0.10(syst). The measurements are compared to various theoretical predictions, including those from perturbative quantum chromodynamics.
Volume
97