Study of the lineshape of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>χ</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>3872</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> state
R. Aaij, C. Abellán Beteta, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. A. Aidala, S. Aiola, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, Z. Aliouche, G. Alkhazov, P. Álvarez Cartelle, A. A. Alves, S. Amato, Y. Amhis, L. An, L. Anderlini, G. Andreassi, A. Andreianov, M. Andreotti, F. Archilli, A. Artamonov, M. Artuso, Kenenbek Arzymatov, E. Aslanides, M. Atzeni, B. Audurier, S. Bachmann, Marie Bachmayer, J. J. Back, S. Baker, P. Baladrón Rodríguez, V. Balagura, W. Baldini, J. Baptista de Souza Leite, R. J. Barlow, S. Barsuk, W. Barter, M. Bartolini, F. Baryshnikov, J. M. Basels, G. Bassi, V. Batozskaya, B. Batsukh, A. Battig, A. Bay, M. Becker, F. Bedeschi, I. Bediaga, A. Beiter, V. Belavin, S. Belin, V. Bellée, K. Belous, I. Belyaev, G. Bencivenni, E. Ben-Haim, S. Benson, A. Berezhnoy, R. Bernet, D. Berninghoff, H. C. Bernstein, C. Bertella, E. Bertholet, A. Bertolin, C. Betancourt, F. Betti, M. O. Bettler, Ia. Bezshyiko, S. Bhasin, J. Bhom, L. Bian, M. S. Bieker, S. Bifani, P. Billoir, F. C. R. Bishop, A. Bizzeti, M. Bjørn, M. P. Blago, T. Blake, F. Blanc, S. Blusk, D. Bobulska, V. Bocci, J. A. Boelhauve, O. Boente García, A. Bohare, A. Boldyrev, A. Bondar, N. Bondar, S. Borghi, M. Borisyak, M. Borsato, J. T. Borsuk, S. A. Bouchiba
Abstract
A study of the lineshape of the c1 3872 state is made using a data sample corresponding to an integrated luminosity of 3 fb -1 collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate c1 3872 and 2S mesons from b-hadron decays are selected in the J= -decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the c1 3872 and 2S states, m, and the width of the c1 3872 state, BW , are determined to be m185.598AE0.067AE0.068 MeV; BW 1.39AE0.24AE0.10 MeV; where the first uncertainty is statistical and the second systematic. Using a Flattinspired model, the mode and full width at half maximum of the lineshape are determined to be mode3871.69 0.000.05 -0.04-0.13 MeV; FWHM0.22 0.070.11 -0.06-0.13 MeV: An investigation of the analytic structure of the Flatt amplitude reveals a pole structure, which is compatible with a quasibound D 0 D0 state but a quasivirtual state is still allowed at the level of 2 standard deviations.