1,306 research outputs found
Why is TeV-scale a geometric mean of neutrino mass and GUT-scale?
Among three typical energy scales, a neutrino mass scale ( 0.1
eV), a GUT scale ( GeV), and a TeV-scale (
TeV), there is a fascinating relation of . The TeV-scale, , is a new physics scale beyond the standard
model which is regarded as supersymmetry in this letter. We suggest a simple
supersymmetric neutrinophilic Higgs doublet model, which realizes the above
relation dynamically as well as the suitable through a tiny vacuum
expectation value of neutrinophilic Higgs without additional scales other than
and . A gauge coupling unification, which is an excellent
feature in the supersymmetric standard model, is preserved automatically in
this setup.Comment: 7 page
Measurement of the near-threshold cross section using initial-state radiation
We report measurements of the exclusive cross section for , where or , in the center-of-mass energy range from the threshold to with initial-state radiation. The
analysis is based on a data sample collected with the Belle detector with an
integrated luminosity of 673 .Comment: Presented at EPS07 and LP07 conferences, published in PRD(RC
Charge Asymmetry of Same-Sign Dileptons in - Mixing
We report a measurement of the charge asymmetry for same-sign dileptons in
- mixing, . The data were collected with the Belle
detector at KEKB. Using a data sample of 78 fb recorded at the
resonance and 9 fb recorded at an energy 60 MeV below the
resonance, we measure .Comment: 21 pages, 9 figures, 3 tables, submitted to Physical Review
Measurement of CP Asymmetries and Branching Fractions in a Time-Dependent Dalitz Analysis of B^0-->(rho pi)^0 and a Constraint on the Quark Mixing Angle phi_2
We present the results of a time-dependent Dalitz plot analysis of B0 --> pi+
pi- pi0 decays based on a 414/fb data sample that contains 449 x 10^6 BB pairs.
The data was collected on the Upsilon(4S) resonance with the Belle detector at
the KEKB asymmetric energy e+e- collider. Combining our analysis with
information on charged B decay modes, we perform a full Dalitz and isospin
analysis and obtain a constraint on the quark mixing angle phi_2, 68deg. <
phi_2 < 95deg. at the 68.3% confidence level for the phi_2 solution consistent
with the standard model (SM). A large SM-disfavored region also remains. The
branching fractions for the decay processes of B0 --> rho+-(770) pi-+ and B0
--> rho0(770) pi0 are measured to be (22.6 +- 1.1[stat.] +- 4.4 [syst.]) x
10^{-6} and (3.0 +- 0.5 [stat.] +- 0.7 [syst.]) x 10^{-6}, respectively. These
are the first branching fraction measurements of the process B0 --> rho(770)pi
with the lowest resonance rho(770) explicitly separated from the radial
excitations.Comment: 26 pages, 12 figures, to be submitted to Phys. Rev. D; Revision to
Phys. Rev. D published versio
Improved Measurements of Partial Rate Asymmetry in B -> h h Decays
We report improved measurements of the partial rate asymmetry (Acp) in B -> h
h decays with 140fb^-1 of data collected with the Belle detector at the KEKB
e+e- collider. Here h stands for a charged or neutral pion or kaon and in total
five decay modes are included: K-+ pi+-, K0s pi-+, K-+ pi0, pi-+ pi0 and K0s
pi0. The flavor of the last decay mode is determined from the accompanying B
meson. Using a data sample 4.7 times larger than that of our previous
measurement, we find Acp(K-+ pi+-) -0.088+-0.035+-0.013, 2.4 sigma from zero.
Results for other decay modes are also presented.Comment: 9 pages, 1 figur
Observation of Radiative Decay
We report the observation of the decay with a
statistical significance of in 78.1 \ifb of data collected by the
Belle experiment at the KEKB collider. This is the first observation
of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and
color-suppressed decays , are also observed for
the first time. We measure branching fractions \br(D^{0} \to \phi \gamma)
= [ 2.60^{+0.70}_{-0.61} \stat {}^{+0.15}_{-0.17} \syst ] \times 10^{-5},
\br(D^{0} \to \phi \pi^{0})
= [ 8.01 \pm 0.26 \stat \pm 0.47 \syst ] \times 10^{-4}, and \br(D^{0} \to
\phi \eta) = [ 1.48 \pm 0.47 \stat \pm 0.09 \syst ] \times 10^{-4}.Comment: 9 pages, 4 figures, Belle Preprint 2003-24, KEK Preprint 2003-75,
updated version of BELLE-CONF-0346 (contributed paper to the XXI
International Symposium on Lepton and Photon Interactions at High
Energies,Fermilab Aug 11-16,2003). to appear in Phys. Rev. Let
Observation of Ds1(2536)+ -> D+pi-K+ and angular decomposition of Ds1(2536)+ -> D*+K0S
Using 462/fb of e+e- annihilation data recorded by the Belle detector, we
report the first observation of the decay Ds1(2536)+ -> D+pi-K+. The ratio of
branching fractions B(Ds1+ -> D+pi-K+)/B(Ds1+ -> D*+K0) is measured to be
(3.27+-0.18+-0.37)%. We also study the angular distributions in the Ds1(2536)+
-> D*+K0S decay and measure the ratio of D- and S-wave amplitudes. The S-wave
dominates, with a partial width of Gamma_S/Gamma_total=0.72+-0.05+-0.01.Comment: Submitted to Phys.Rev.D 16 pages, 6 figures, 3 table
Search for new charmonium states in the processes e+ e- --> J/psi D(*) D(*) at sqrt{s} ~ 10.6 GeV
We present a study of the X(3940) state in the process e+e- -> J/psi D* Dbar.
The X(3940) mass and width are measured to be (3942 +7 -6 +- 6)MeV/c^2 and
Gamma=(37 + 26 - 15 +- 8 MeV. In the process e+e- -> J/psi D* D*bar we have
observed another charmonium-like state, which we denote as X(4160), in the
spectrum of invariant masses of D*+ D*- combinations. The X(4160) parameters
are M= 4156 + 25 - 20 +- 15 MeV/c^2 and Gamma = 139 + 111 -61 +- 21 MeV. The
analysis is based on a data sample with an integrated luminosity of 693 /fb
recorded near the Upsilon(4S) resonance with the Belle detector at the KEKB e+
e- asymmetric-energy collider.Comment: 7 pages, 2 figures Contribution paper for conferences EPS2007 and
Lepton Photon 2007, Belle-Conference-070
Time-Dependent {\boldmath }-Violating Asymmetry in Decays
We report the first measurement of CP-violation parameters in
decays based on a data sample of pairs collected with the Belle detector at the KEKB asymmetric-energy
collider. The flavor of the meson is identified from the decay
products of the accompanying meson. We obtain the time-dependent and direct
CP-violating parameters, \cals_{\rhoz\gamma} = -0.83\pm 0.65(stat)\pm
0.18(syst) and \cala_{\rhoz\gamma} = -0.44\pm 0.49(stat)\pm 0.14(syst),
respectively.Comment: 8 pages, 2 figures, published in PR
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