4,941 research outputs found
Fourth Family Neutrinos and the Higgs Boson
We evaluate the LHC discovery potential for the fourth family Standard Model
neutrinos in the process . We
show that, depending on their masses, the simultaneous discovery of both the
Higgs boson and the heavy neutrinos is probable at early stages of LHC
operation. Results are presented for both Majorana and Dirac type fourth family
neutrinos.Comment: 12 pages, uses axodraw.sty, v2: includes typo fixes, improved
analysis, v4: minor modifications in response to the JHEP refere
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Rare B Decays in Collider Experiments
The recent results on the semileptonic and leptonic rare B decays from the collider experiments are reviewed. Additionally, the recent measurements of lepton flavor violation in {tau} decays are presented
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Radiative Penguin Decays at the B Factories
Recent results from the B-Factories on radiative decays such as b {yields} s(d){gamma}, b {yields} s{ell}{ell} and leptonic decay B{sup 0} {yields} {tau}{sup +}{tau}{sup -} are reviewed
Possible Discovery Channel for New Charged Leptons at the LHC
We propose a channel for the possible discovery of new charged leptons at the
Large Hadron Collider. The proposed final state contains three same-sign
leptons, making this new channel practically back- groundless. The method is
illustrated for two different cases: the four-family Standard Model and the
Grand Unified Theory based on the E6 gauge group. An example study taking 250
GeV as the charged lepton mass shows that in both models, about 8 signal events
can be expected at 14 TeV center-of-mass energy with 1 fb^-1 of integrated
luminosity. Although the event yield might not be sufficient for detailed
measurements of the charged lepton properties, it would be sufficient to claim
discovery through a counting experiment.Comment: 8 pages, 4 figures. v2 update includes an estimate of the
backgrounds, consideration of the EW oblique parameters, and minor
improvements. v3 update includes detector acceptance and ttbar backgroun
The Fourth Standard Model Family and the Competition in Standart Model Higgs Boson Search at Tevatron and LHC
The impact of the fourth Standard Model family on Higgs boson search at
Tevatron and LHC is reviewed.Comment: 7 pages, 13 figure
Neutrino masses from new generations
We reconsider the possibility that Majorana masses for the three known
neutrinos are generated radiatively by the presence of a fourth generation and
one right-handed neutrino with Yukawa couplings and a Majorana mass term. We
find that the observed light neutrino mass hierarchy is not compatible with low
energy universality bounds in this minimal scenario, but all present data can
be accommodated with five generations and two right-handed neutrinos. Within
this framework, we explore the parameter space regions which are currently
allowed and could lead to observable effects in neutrinoless double beta decay,
conversion in nuclei and experiments. We
also discuss the detection prospects at LHC.Comment: 28 pages, 4 figures. Version to be published. Some typos corrected.
Improved figures 3 and
Measurement of the Branching Fraction for B- --> D0 K*-
We present a measurement of the branching fraction for the decay B- --> D0
K*- using a sample of approximately 86 million BBbar pairs collected by the
BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is
detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the
K*- through its decay to K0S pi-. We measure the branching fraction to be
B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid
Communications
Search for the W-exchange decays B0 --> Ds(*)- Ds(*)+
We report a search for the decays , , in a sample of 232
million decays to \BBb ~pairs collected with the \babar detector
at the PEP-II asymmetric-energy storage ring. We find no significant
signal and set upper bounds for the branching fractions: and at 90% confidence level.Comment: 8 pages, 2 figures, submitted to PRD-R
Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays
We present measurements of the branching fractions for the three-body decays
B0 -> D(*)-/+ K0 pi^+/-B0 -> D(*)-/+ K*+/- using
a sample of approximately 88 million BBbar pairs collected by the BABAR
detector at the PEP-II asymmetric energy storage ring.
We measure:
B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4}
B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4}
B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4}
B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 10^{-4}
From these measurements we determine the fractions of resonant events to be :
f(B0-> D-/+ K*+/-) = 0.63 +/- 0.08(stat) +/- 0.04(syst) f(B0-> D*-/+ K*+/-) =
0.72 +/- 0.14(stat) +/- 0.05(syst)Comment: 7 pages, 3 figures submitted to Phys. Rev. Let
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