Searching for light Dark Matter in heavy meson decays (original) (raw)
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Inclusive charmed-meson production from bottom hadron decays at the LHC
Journal of Physics G: Nuclear and Particle Physics, 2014
We present predictions for the inclusive productions of the D meson originating from bottom hadrons at the CERN LHC in the general-mass variable-flavour-number scheme at next-to-leading order. We present results using two methods to describe the transition for b → D: a two-step transition b → B → D, based on the b → B fragmentation functions and the spectra for B → D as measured by CLEO and a one-step transition based on the fragmentation functions for b → D. The results of both approaches are compared.
Physical Review D, 2010
We have searched for flavor-changing neutral current decays and lepton-number-violating decays of D + and D + s mesons to final states of the form h ± e ∓ e + , where h is either π or K. We use the complete samples of CLEO-c open-charm data, corresponding to integrated luminosities of 818 pb −1 at the center-of-mass energy E CM = 3.774 GeV containing 2.4×10 6 D + D − pairs and 602 pb −1 at E CM = 4.170 GeV containing 0.6 × 10 6 D * ± s D ∓ s pairs. No signal is observed in any channel, and we obtain 90% confidence level upper limits on branching fractions B(D + → π + e + e − ) < 5.9×10 −6 , B(D + → π − e + e + ) < 1.1×10 −6 , B(D + → K + e + e − ) < 3.0×10 −6 , B(D + → K − e + e + ) < 3.5×10 −6 , B(D + s → π + e + e − ) < 2.2 × 10 −5 , B(D + s → π − e + e + ) < 1.8 × 10 −5 , B(D + s → K + e + e − ) < 5.2 × 10 −5 , and B(D + s → K − e + e + ) < 1.7 × 10 −5 .
Charmed-strange mesons revisited: Mass spectra and strong decays
Physical Review D, 2015
Inspired by the present experimental status of charmed-strange mesons, we perform a systematic study of the charmed-strange meson family, in which we calculate the mass spectra of the charmed-strange meson family by taking a screening effect into account in the Godfrey-Isgur model and investigate the corresponding strong decays via the quark pair creation model. These phenomenological analyses of charmed-strange mesons not only shed light on the features of the observed charmed-strange states, but also provide important information on future experimental search for the missing higher radial and orbital excitations in the charmed-strange meson family, which will be valuable task in LHCb, forthcoming BelleII and PANDA.
Study of inclusive production of charmonium mesons in B decays
Physical Review D
The inclusive production of charmonium mesons in B meson decay has been studied in a 20.3 fb -1 data set collected by the BABAR experiment operating at the Υ(4S) resonance. Branching fractions have been measured for the inclusive production of the charmonium mesons ...
Measurement of inclusive production of charmonium states in B meson decays
2000
We reconstruct the charmonium mesons J/ψ , ψ(2S) and χ c using a sample of 8.46 × 10 6 BB events collected by the BABAR detector operating at e + e − center of mass energies near the Υ (4S) resonance. By measuring rates relative to the branching fraction of the J/ψ , we obtain preliminary inclusive B branching fractions of (0.25 ± 0.02 ± 0.02)% to the ψ(2S) and (0.39 ± 0.04 ± 0.04)% to the χ c1 , and set a 90% confidence level limit of 0.24% on decays through the χ c2 .
A search for pair production of new light bosons decaying into muons
A search for new light bosons decaying into muon pairs is presented using a data sample corresponding to an integrated luminosity of 35.9 fb −1 of proton-proton collisions at a center-of-mass energy √ s = 13 TeV, collected with the CMS detector at the CERN LHC. The search is model independent, only requiring the pair production of a new light boson and its subsequent decay to a pair of muons. No significant deviation from the predicted background is observed. A model independent limit is set on the product of the production cross section times branching fraction to dimuons squared times acceptance as a function of new light boson mass. This limit varies between 0.15 and 0.39 fb over a range of new light boson masses from 0.25 to 8.5 GeV. It is then interpreted in the context of the next-to-minimal supersymmetric standard model and a dark supersymmetry model that allows for nonnegligible light boson lifetimes. In both cases, there is significant improvement over previously published limits.
Study of χc1 and χc2 meson production in B meson decays
Physical Review D, 2001
Using a sample of 9.7 × 10 6 BB meson pairs collected with the CLEO detector, we study B decays to the χ c1 and χ c2 charmonia states, which are reconstructed via their radiative decays to J/ψ. We first measure the branching fraction for inclusive χ c1 production in B decays to be B(B → χ c1 X) = (4.14 ± 0.31 ± 0.40) × 10 −3 , where the first uncertainty is statistical and the second one is systematic. We derive the branching fractions for direct χ c1 and χ c2 production in B decays by subtracting the known contribution of the decay chain B → ψ(2S)X with ψ(2S) → χ c1,2 γ. We obtain B[B → χ c1 (direct)X] = (3.83 ± 0.31 ± 0.40) × 10 −3 . No statistically significant signal for χ c2 production is observed in either case. Using the Feldman-Cousins approach, we determine the 95% confidence intervals to be [0.2, 2.0] × 10 −3 for B(B → χ c2 X), [0.0, 1.7] × 10 −3 for B[B → χ c2 (direct)X], and [0.00, 0.44] for the ratio Γ[B → χ c2 (direct)X]/Γ[B → χ c1 (direct)X]. We also measure the branching ratio Γ[B → χ c2 (direct)X s ]/Γ[B → χ c1 (direct)X s ] for different X s configurations by reconstructing B decays into exclusive final states with J/ψ, γ, a kaon, and up to four pions. For all the X s configurations we observe a strong χ c1 signal yet no statistically significant χ c2 signal. We discuss how our results compare with theoretical predictions in different models of charmonium production.