Searches for Majorana neutrinos in B- decays Abellan Beteta, Carlos; Calvo Gómez, Míriam; Camboni, Alessandro ...
Physical review. D, Particles, fields, gravitation, and cosmology,
06/2012
Journal Article
Odprti dostop
Searches for heavy Majorana neutrinos in B − decays in final states containing hadrons plus a μ − μ − pair have been performed using 0.41 fb − 1 of data collected with the LHCb detector in ...proton-proton collisions at a center-of-mass energy of 7 TeV. The D + μ − μ − and D * + μ − μ − final states can arise from the presence of virtual Majorana neutrinos of any mass. Other final states containing π + , D + s , or D 0 π + can be mediated by an on-shell Majorana neutrino. No signals are found and upper limits are set on Majorana neutrino production as a function of mass, and also on the B − decay branching fractions.
Searches for Majorana neutrinos in B- decays Abellan Beteta, Carlos; Calvo Gómez, Míriam; Camboni, Alessandro ...
Physical review. D, Particles, fields, gravitation, and cosmology,
06/2012
Journal Article
Odprti dostop
Searches for heavy Majorana neutrinos in B − decays in final states containing hadrons plus a μ − μ − pair have been performed using 0.41 fb − 1 of data collected with the LHCb detector in ...proton-proton collisions at a center-of-mass energy of 7 TeV. The D + μ − μ − and D * + μ − μ − final states can arise from the presence of virtual Majorana neutrinos of any mass. Other final states containing π + , D + s , or D 0 π + can be mediated by an on-shell Majorana neutrino. No signals are found and upper limits are set on Majorana neutrino production as a function of mass, and also on the B − decay branching fractions.
The ratio of branching fractions of the radiative B decays B 0 → K * 0 γ and B 0 s → ϕ γ has been measured using 0.37 fb − 1 of p p collisions at a center of mass energy of √ s = 7 TeV , ...collected by the LHCb experiment. The value obtained is B ( B 0 → K * 0 γ ) B ( B 0 s → ϕ γ ) = 1.12 ± 0.08 + 0.06 + 0.09 − 0.04 − 0.08 , where the first uncertainty is statistical, the second systematic, and the third is associated with the ratio of fragmentation fractions f s / f d . Using the world average for B ( B 0 → K * 0 γ ) = ( 4.33 ± 0.15 ) × 10 − 5 , the branching fraction B ( B 0 s → ϕ γ ) is measured to be ( 3.9 ± 0.5 ) × 10 − 5 , which is the most precise measurement to date.
The ratio of branching fractions of the radiative B decays B 0 → K * 0 γ and B 0 s → ϕ γ has been measured using 0.37 fb − 1 of p p collisions at a center of mass energy of √ s = 7 TeV , ...collected by the LHCb experiment. The value obtained is B ( B 0 → K * 0 γ ) B ( B 0 s → ϕ γ ) = 1.12 ± 0.08 + 0.06 + 0.09 − 0.04 − 0.08 , where the first uncertainty is statistical, the second systematic, and the third is associated with the ratio of fragmentation fractions f s / f d . Using the world average for B ( B 0 → K * 0 γ ) = ( 4.33 ± 0.15 ) × 10 − 5 , the branching fraction B ( B 0 s → ϕ γ ) is measured to be ( 3.9 ± 0.5 ) × 10 − 5 , which is the most precise measurement to date.
Search for the X(4140) state in B+→J/ψϕK+ decays Abellan Beteta, Carlos; Calvo Gómez, Míriam; Camboni, Alessandro ...
Physical review. D, Particles, fields, gravitation, and cosmology,
05/2012
Journal Article
Odprti dostop
A search for the X ( 4140 ) state in B + → J / ψ ϕ K + decays is performed with 0.37 fb − 1 of p p collisions at √ s = 7 TeV collected by the LHCb experiment. No evidence for this state is ...found, in 2.4 σ disagreement with a measurement by CDF. An upper limit on its production rate is set, B ( B + → X ( 4140 ) K + ) × B ( X ( 4140 ) → J / ψ ϕ ) / B ( B + → J / ψ ϕ K + ) < 0.07 at 90% confidence level.
A study of B ± → J / ψ π ± and B ± → ψ ( 2 S ) π ± decays is performed with data corresponding to 0.37 fb − 1 of proton-proton collisions at √ s = 7 TeV . Their branching fractions are found ...to be B ( B ± → J / ψ π ± ) = ( 3.88 ± 0.11 ± 0.15 ) × 10 − 5 and B ( B ± → ψ ( 2 S ) π ± ) = ( 2.52 ± 0.26 ± 0.15 ) × 10 − 5 , where the first uncertainty is related to the statistical size of the sample and the second quantifies systematic effects. The measured C P asymmetries in these modes are A J / ψ π C P = 0.005 ± 0.027 ± 0.011 and A ψ ( 2 S ) π C P = 0.048 ± 0.090 ± 0.011 with no evidence of direct C P violation seen.
A study of B ± → J / ψ π ± and B ± → ψ ( 2 S ) π ± decays is performed with data corresponding to 0.37 fb − 1 of proton-proton collisions at √ s = 7 TeV . Their branching fractions are found ...to be B ( B ± → J / ψ π ± ) = ( 3.88 ± 0.11 ± 0.15 ) × 10 − 5 and B ( B ± → ψ ( 2 S ) π ± ) = ( 2.52 ± 0.26 ± 0.15 ) × 10 − 5 , where the first uncertainty is related to the statistical size of the sample and the second quantifies systematic effects. The measured C P asymmetries in these modes are A J / ψ π C P = 0.005 ± 0.027 ± 0.011 and A ψ ( 2 S ) π C P = 0.048 ± 0.090 ± 0.011 with no evidence of direct C P violation seen.
Search for the X(4140) state in B+→J/ψϕK+ decays Abellan Beteta, Carlos; Calvo Gómez, Míriam; Camboni, Alessandro ...
Physical review. D, Particles, fields, gravitation, and cosmology,
05/2012
Journal Article
Odprti dostop
A search for the X ( 4140 ) state in B + → J / ψ ϕ K + decays is performed with 0.37 fb − 1 of p p collisions at √ s = 7 TeV collected by the LHCb experiment. No evidence for this state is ...found, in 2.4 σ disagreement with a measurement by CDF. An upper limit on its production rate is set, B ( B + → X ( 4140 ) K + ) × B ( X ( 4140 ) → J / ψ ϕ ) / B ( B + → J / ψ ϕ K + ) < 0.07 at 90% confidence level.
A study of B ± → J / ψ π ± and B ± → ψ ( 2 S ) π ± decays is performed with data corresponding to 0.37 fb − 1 of proton-proton collisions at √ s = 7 TeV . Their branching fractions are found ...to be B ( B ± → J / ψ π ± ) = ( 3.88 ± 0.11 ± 0.15 ) × 10 − 5 and B ( B ± → ψ ( 2 S ) π ± ) = ( 2.52 ± 0.26 ± 0.15 ) × 10 − 5 , where the first uncertainty is related to the statistical size of the sample and the second quantifies systematic effects. The measured C P asymmetries in these modes are A J / ψ π C P = 0.005 ± 0.027 ± 0.011 and A ψ ( 2 S ) π C P = 0.048 ± 0.090 ± 0.011 with no evidence of direct C P violation seen.
Measurements of b hadron production ratios in proton-proton collisions at a center-of-mass energy of 7 TeV with an integrated luminosity of 3 pb − 1 are presented. We study the ratios of strange ...B meson to light B meson production f s / ( f u + f d ) and Λ 0 b baryon to light B meson production f Λ b / ( f u + f d ) as a function of the charmed hadron-muon pair transverse momentum p T and the b hadron pseudorapidity η , for p T between 0 and 14 GeV and η between 2 and 5. We find that f s / ( f u + f d ) is consistent with being independent of p T and η , and we determine f s / ( f u + f d ) = 0.134 ± 0.004 + 0.011 − 0.010 , where the first error is statistical and the second systematic. The corresponding ratio f Λ b / ( f u + f d ) is found to be dependent upon the transverse momentum of the charmed hadron-muon pair, f Λ b / ( f u + f d ) = ( 0.404 ± 0.017 ( stat ) ± 0.027 ( syst ) ± 0.105 ( Br ) ) × 1 − ( 0.031 ± 0.004 ( stat ) ± 0.003 ( syst ) ) × p T ( GeV ) , where Br reflects an absolute scale uncertainty due to the poorly known branching fraction B ( Λ + c → p K − π + ) . We extract the ratio of strange B meson to light neutral B meson production f s / f d by averaging the result reported here with two previous measurements derived from the relative abundances of ¯¯¯ B 0 s → D + s π − to ¯¯¯ B 0 → D + K − and ¯¯¯ B 0 → D + π − . We obtain f s / f d = 0.267 + 0.021 − 0.020 .
