68,813 research outputs found
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Measurement of the time-dependent CP asymmetry in B0 -> J/ψ KS0 decays
No full textThis Letter reports a measurement of the CP violation observables SJ/ψK0S and CJ/ψK0S in the decay channel B0→J/ψK0S performed with 1.0 fb−1 of pp collisions at s√=7 TeV collected by the LHCb experiment. The fit to the data yields SJ/ψK0S=0.73±0.07(stat)±0.04(syst) and CJ/ψK0S=0.03±0.09(stat)±0.01(syst). Both values are consistent with the current world averages and within
expectations from the Standard Model
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
No full textMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
First determination of the CP content of D → ∏+∏−∏0 and D → K +K −∏0
No full textQuantum-correlated View the MathML source decays collected by the CLEO-c experiment are used to perform first measurements of F+, the fractional CP -even content of the self-conjugate decays D→∏+∏−∏0 and D→K+K−∏0. Values of 0.968±0.017±0.006 and 0.731±0.058±0.021 are obtained for ∏+∏−∏0 and K+K−∏0, respectively. It is demonstrated how modes of this sort can be cleanly included in measurements of the unitarity triangle angle γ using B∓→DK∓ decays. The high CP -even content of D→∏+∏−∏0, in particular, makes this a promising mode for improving the precision on γ
Generalised CP and A4 family symmetry
No full textWe perform a comprehensive study of family symmetry models based on A4 combined with the generalised CP symmetry H CP. We investigate the lepton mixing parameters which can be obtained from the original symmetry A4 ? H CP breaking to different remnant symmetries in the neutrino and charged lepton sectors. We find that only one case is phenomenologically viable, namely G?CP?ZS2×H?CP in the neutrino sector and GlCP?ZT3?HlCP in the charged lepton sector, leading to the prediction of no CP violation, namely ? CP and the Majorana phases ? 21 and ? 31 are all equal to either zero or ?. We then propose an effective supersymmetric model based on the symmetry A4 ? H CP in which trimaximal lepton mixing is predicted together with either zero CP violation or ? CP ? ±?/2 with non-trivial Majorana phases. An ultraviolet completion of the effective model yields a neutrino mass matrix which depends on only three real parameters. As a result of this, all three CP phases and the absolute neutrino mass scale are determined, the atmospheric mixing angle is maximal, and the Dirac CP can either be preserved with ? CP ?=?0, ? or maximally broken with ? CP ?=?±?/2 and sharp predictions for the Majorana phases and neutrinoless double beta deca
Encapsulation efficiency (EE), encapsulation stability (ES) and evolution of betanin total retention in DE-CP, DE-CP-G, DE-CP-GT during storage at 4 °C.
No full textEncapsulation efficiency (EE), encapsulation stability (ES) and evolution of betanin total retention in DE-CP, DE-CP-G, DE-CP-GT during storage at 4 °C.</p
Degradation products of betanin identified in DE-CP, DE-CP-G and DE-CP-GT at the end of storage at 4 °C, and in the samples subjected to thermal treatment (70 °C/30 min).
No full textDegradation products of betanin identified in DE-CP, DE-CP-G and DE-CP-GT at the end of storage at 4 °C, and in the samples subjected to thermal treatment (70 °C/30 min).</p
Measurement of mixing and CP violation parameters in two-body charm decays
No full textA study of mixing and indirect CP violation in D 0 mesons through the determination of the parameters y CP and A Γ is presented. The parameter y CP is the deviation from unity of the ratio of effective lifetimes measured in D 0 decays to the CP eigenstate K + K − with respect to decays to the Cabibbo favoured mode K −π+. The result measured using data collected by LHCb in 2010, corresponding to an integrated luminosity of 29 pb−1, is y CP = (5.5 ± 6.3stat ± 4.1syst) × 10−3. The parameter A Γ is the asymmetry of effective lifetimes measured in decays of D 0 and D0 mesons to K + K −. The result is A Γ = (−5.9 ± 5.9stat ± 2.1syst) × 10−3. A data-driven technique is used to correct for lifetime-biasing effects
Search for CP violation in D + → ϕπ + and D+s→K0Sπ+ decays
No full textA search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%
CP-violation in cascade decays at the LHC
No full textWe study the potential to observe CP-violating effects in various supersymmetric cascade
decay chains at the LHC. Asymmetries composed by triple products of
momenta of the final state particles are sensitive to CP-violating
effects. We analytically calculate the cascade decays including the relevant spin correlations to compute the parton level asymmetry. In addition, we use Monte Carlo simulations to estimate the sensitivity of the LHC to the CP-violating observables.
Due to large boosts that dilute the asymmetries, these can be
difficult to observe at the LHC. However, if all particle masses in a cascade decay are
known, it may be possible to reconstruct all momenta in the decay chains. We can then recover the full asymmetry on an
event-by-event basis even when we have missing momentum due to a stable
lightest supersymmetric particle. After the reconstruction, the non-diluted CP-violating signal gets
significantly enhanced so that an observation may become feasible.
A fully hadronic study has also been completed to produce the best estimate of the viability of these obseravbles at the LHC. We include both standard model and SUSY backgrounds in the study. Our conclusions state that given a favourable scenario, CP-violation may be observed in SUSY at the 3-sigma level over a wide range of CP-phases with 500 1/fb of data
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