An improved search for B-s(0) oscillations is performed in the ALEPH data sample collected during the first phase of LEP, and reprocessed in 1998. Three analyses based on complementary event selections are presented. First, decays of B-s(0) mesons into hadronic flavour eigenstates are fully reconstructed. This selection yields a small sample of candidates with excellent decay length and momentum resolution and high average B-s(0) purity. Semileptonic decays with a reconstructed D-s(-) meson provide a second sample with larger statistics, high average B-s(0) purity, but a poorer momentum and decay length resolution due to the partial decay reconstruction. Finally, semileptonic b-hadron decays are inclusively selected and yield the data sample with the highest sensitivity to B-s(0) oscillations, as the much higher statistics compensate for the low average B-s(0) purity and poorer time resolution. A lower limit is set at Deltam(s) > 10.9 ps(-1) at 95%C.L., significantly lower than the expected limit of 15.2 ps(-1).

Improved search for B-S(0)-(B)over-bar(S)(0) oscillations

ROLANDI, LUIGI;LIGABUE, FRANCO;
2003

Abstract

An improved search for B-s(0) oscillations is performed in the ALEPH data sample collected during the first phase of LEP, and reprocessed in 1998. Three analyses based on complementary event selections are presented. First, decays of B-s(0) mesons into hadronic flavour eigenstates are fully reconstructed. This selection yields a small sample of candidates with excellent decay length and momentum resolution and high average B-s(0) purity. Semileptonic decays with a reconstructed D-s(-) meson provide a second sample with larger statistics, high average B-s(0) purity, but a poorer momentum and decay length resolution due to the partial decay reconstruction. Finally, semileptonic b-hadron decays are inclusively selected and yield the data sample with the highest sensitivity to B-s(0) oscillations, as the much higher statistics compensate for the low average B-s(0) purity and poorer time resolution. A lower limit is set at Deltam(s) > 10.9 ps(-1) at 95%C.L., significantly lower than the expected limit of 15.2 ps(-1).
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/1688
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 14
  • ???jsp.display-item.citation.isi??? 13
social impact