A measurement of the CP asymmetry difference between Λc + → pK K + and pππ+ decays

The LHCb Collaboration, R. Aaij, B. Adeva, M. Adinolfi, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves, S. Amato, S. Amerio, Y. Amhis, L. An, L. Anderlini, G. Andreassi & 31 others M. Andreotti, J. E. Andrews, R. B. Appleby, F. Archilli, P. d’Argent, J. Arnau Romeu, A. Artamonov, M. Artuso, E. Aslanides, M. Atzeni, G. Auriemma, M. Baalouch, I. Babuschkin, S. Bachmann, J. J. Back, A. Badalov, C. Baesso, S. Baker, V. Balagura, W. Baldini, A. Baranov, R. J. Barlow, C. Barschel, S. Barsuk, W. Barter, F. Baryshnikov, V. Batozskaya, V. Battista, A. Mazurov, A. Petrov, A. Vagner

Research output: Contribution to journalArticle

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Abstract

The difference between the CP asymmetries in the decays Λc + → pKK+ and Λc + → pππ+ is presented. Proton-proton collision data taken at centre-of-mass energies of 7 and 8 TeV collected by the LHCb detector in 2011 and 2012 are used, corresponding to an integrated luminosity of 3 fb−1. The Λc + candidates are reconstructed as part of the Λb 0 → Λc +μX decay chain. In order to maximize the cancellation of production and detection asymmetries in the difference, the final-state kinematic distributions of the two samples are aligned by applying phase-space-dependent weights to the Λc + → pππ+ sample. This alters the definition of the integrated CP asymmetry to ACP wgt(pππ+). Both samples are corrected for reconstruction and selection efficiencies across the five-dimensional Λc + decay phase space. The difference in CP asymmetries is found to be ΔACPwgt=ACP(pK−K+)−ACPwgt(pπ−π+)=(0.30±0.91±0.61)%, where the first uncertainty is statistical and the second is systematic.[Figure not available: see fulltext.].

LanguageEnglish
Article number182
JournalJournal of High Energy Physics
Volume2018
Issue number3
DOIs
Publication statusPublished - 1 Mar 2018

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asymmetry
decay
protons
cancellation
center of mass
kinematics
luminosity
collisions
detectors
energy

Keywords

  • Charm physics
  • CP violation
  • Flavor physics
  • Hadron-Hadron scattering (experiments)

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

A measurement of the CP asymmetry difference between Λc + → pK K + and pππ+ decays. / The LHCb Collaboration.

In: Journal of High Energy Physics, Vol. 2018, No. 3, 182, 01.03.2018.

Research output: Contribution to journalArticle

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