共查询到20条相似文献,搜索用时 31 毫秒
1.
Zhi-Gang Luo Xiao-Lin Chen Xiang Liu Shi-Lin Zhu 《The European Physical Journal C - Particles and Fields》2009,60(3):403-411
Stimulated by recent observations of the excited bottom–strange mesons B
s1 and B
s2*, we calculate the semileptonic decays
, which is relevant for the exploration of the potential of searching these semileptonic decays in experiment. 相似文献
2.
Junfeng Sun Dongsheng Du Yueling Yang 《The European Physical Journal C - Particles and Fields》2009,60(1):107-117
The B
c
→J/ψ
π, η
c
π decays are studied with the perturbative QCD approach. It is found that the form factors
and
for the B
c
→J/ψ, η
c
transitions and the branching ratios are sensitive to the parameters ω, v, f
J/ψ
and
, where ω and v are the parameters of the charmonium wave functions for a Coulomb potential and the harmonic-oscillator potential, respectively,
and f
J/ψ
and
are the decay constants of the J/ψ and η
c
mesons, respectively. The large branching ratios and the clear signals of the final states make the B
c
→J/ψ
π, η
c
π decays the prospective channels for measurements at the hadron colliders. 相似文献
3.
J. Stanzel F. Burmeister M. Neeb 《Applied Physics A: Materials Science & Processing》2010,100(1):21-29
We have studied the dynamics of photoexcited tungsten cluster anions Wn-\mathrm{W}_{n}^{-} (n=3,4,…,14) by means of time-resolved two-photon photodetachment spectroscopy. At an excitation energy of h
ν
pump=1.56 eV the photoinduced dynamics is mainly dominated by fast electronic relaxation processes. For the smallest clusters,
i.e., W3-\mathrm{W}_{3}^{-}, W4-\mathrm{W}_{4}^{-}, and W5-\mathrm{W}_{5}^{-}, individual relaxation channels have been identified and resolved on a timescale well below 100 fs. The time constants for
the decay of nascent and secondary electrons have been deduced from a Bloch model. Complete thermalization takes place for
all clusters on a timescale of ∼1 ps. 相似文献
4.
Dae Sung Hwang Hyungsuk Son 《The European Physical Journal C - Particles and Fields》2010,67(1-2):111-116
We calculate the decay rate ratios for OZI allowed decays of ?(5S) to two B mesons by using the decay amplitudes which incorporate the wave function of the ?(5S) state. We obtain the result that the branching ratio of the ?(5S) decay to $B_{s}^{*}{\bar{B}}_{s}^{*}$ is much larger than the branching ratio to $B_{s}{\bar{B}}_{s}^{*}$ or ${\bar{B}}_{s}B_{s}^{*}$ , in good agreement with the recent experimental results of CLEO and BELLE. This agreement with the experimental results is made possible since the nodes of the ?(5S) radial wave function induce the nodes of the decay amplitude. We find that the results for the ?(5S) decays to $B_{u}^{(*)}{\bar{B}}_{u}^{(*)}$ or $B_{d}^{(*)}{\bar{B}}_{d}^{(*)}$ pairs are sensitive to the parameter values used for the potential between heavy quarks. 相似文献
5.
Zhi Yang Xing-Gang Wu Li-Cheng Deng Jia-Wei Zhang Gu Chen 《The European Physical Journal C - Particles and Fields》2011,71(3):1563
In Deng et al. (Eur. Phys. J. C 70:113, 2010), we have dealt with the production of the two color-singlet S-wave (c[`(b)])(c\bar{b})-quarkonium states Bc(|(c[`(b)])1[1S0]?)B_{c}(|(c\bar {b})_{\mathbf{1}}[^{1}S_{0}]\rangle) and B*c(|(c[`(b)])1[3S1]?)B^{*}_{c}(|(c\bar{b})_{\mathbf{1}}[^{3}S_{1}]\rangle) through the Z
0 boson decays. As an important sequential work, we make a further discussion on the production of the more complicated P-wave excited (c[`(b)])(c\bar{b})-quarkonium states, i.e. |(c[`(b)])1[1P1]?|(c\bar{b})_{\mathbf{1}}[^{1}P_{1}]\rangle and |(c[`(b)])1[3PJ]?|(c\bar{b})_{\mathbf{1}}[^{3}P_{J}]\rangle (with J=(1,2,3)). More over, we also calculate the channel with the two color-octet quarkonium states |(c[`(b)])8[1S0]g?|(c\bar{b})_{\mathbf{8}}[^{1}S_{0}]g\rangle and |(c[`(b)])8[3S1]g?|(c\bar{b})_{\mathbf{8}}[^{3}S_{1}]g\rangle, whose contributions to the decay width maybe at the same order of magnitude as that of the color-singlet P-wave states according to the naive nonrelativistic quantum chromodynamics scaling rules. The P-wave states shall provide sizable contributions to the B
c
production, whose decay width is about 20% of the total decay width
\varGamma Z0? Bc\varGamma _{Z^{0}\to B_{c}}. After summing up all the mentioned (c[`(b)])(c\bar {b})-quarkonium states’ contributions, we obtain
\varGamma Z0? Bc=235.9+352.8-122.0\varGamma _{Z^{0}\to B_{c}}=235.9^{+352.8}_{-122.0} KeV, where the errors are caused by the main sources of uncertainty. 相似文献
6.
Li-Cheng Deng Xing-Gang Wu Zhi Yang Zhen-Yun Fang Qi-Li Liao 《The European Physical Journal C - Particles and Fields》2010,70(1-2):113-124
The planned new e + e ? collider with high luminosity shall provide another useful platform to study the properties of the doubly heavy B c meson in addition to the hadronic colliders as LHC and TEVATRON. In the ‘New Trace Amplitude Approach’, we calculate the production of the spin-singlet B c and the spin-triplet $B^{*}_{c}$ mesons through the Z 0 boson decays, where uncertainties for the production are also discussed. Our results show $\varGamma_{(^{1}S_{0})}=81.4^{+102.1}_{-40.5}$ KeV and $\varGamma_{(^{3}S_{1})}=116.4^{+163.9}_{-62.8}$ KeV, where the errors are caused by varying m b and m c within their reasonable regions. 相似文献
7.
Alakabha Datta David London Joaquim Matias Makiko Nagashima Alejandro Szynkman 《The European Physical Journal C - Particles and Fields》2009,60(2):279-284
Certain B
s
0→V
1
V
2 decays (V
i
is a vector meson) can be related by flavor SU(3) symmetry to corresponding B
d
0→V
3
V
4 decays. In this paper, we show that the final-state polarization can be predicted in the B
s
0 decay, assuming polarization measurements of the B
d
0 decay. This can be done within the scenario of penguin annihilation (PA), which has been suggested as an explanation of the
unexpectedly large transverse polarization in B→φ
K
*. PA is used to estimate the breaking of flavor SU(3) symmetry in pairs of decays. Two of these for which PA makes a reasonably
precise prediction of the size of SU(3) breaking are (B
s
0→φ
φ,B
d
0→φ
K
0*) and (
). The polarization measurement in the B
d
0 decay can be used to predict the transverse polarization in the B
s
0 decay and will allow for testing of PA as well as the other assumptions in the analysis. 相似文献
8.
Let p≥2, n
1≤⋅⋅⋅≤n
p
be positive integers and
be independent planar Brownian motions started uniformly on the boundary of the unit circle. We define a p-fold intersection exponent ς
p
(n
1,…,n
p
), as the exponential rate of decay of the probability that the packets
, i=1,…,p, have no joint intersection. The case p=2 is well-known and, following two decades of numerical and mathematical activity, Lawler et al. (Acta Math. 187:275–308,
2001) rigorously identified precise values for these exponents. The exponents have not been investigated so far for p>2. We present an extensive mathematical and numerical study, leading to an exact formula in the case n
1=1, n
2=2, and several interesting conjectures for other cases. 相似文献
9.
Ching Hung Lam 《Communications in Mathematical Physics》2011,305(1):153-198
In this article, we construct explicitly several holomorphic vertex operator algebras of central charge 24 using Virasoro
frames. The Lie algebras associated to their weight one subspaces are of the types A1,2 A3,44, A1,2D5,8, A1,13A7,4{A_{1,2} {A_{3,4}}^4, A_{1,2}D_{5,8}, {A_{1,1}}^3A_{7,4}} , A1,12 C3,2 D5,4, A2,12 A5,22 C2,1, A3,1 A7,2 C3,12, A3,1C7,2{{A_{1,1}}^2 C_{3,2} D_{5,4}, {A_{2,1}}^2 {A_{5,2}}^2 C_{2,1}, A_{3,1} A_{7,2} {C_{3,1}}^2, A_{3,1}C_{7,2}} , A4,1 A9,2B3,1, B4,1 C6,12{A_{4,1} A_{9,2}B_{3,1}, B_{4,1} {C_{6,1}}^2} and B
6,1
C
10,1. These vertex operator algebras correspond to number 7, 10, 18, 19, 26, 33, 35, 40, 48 and 56 in Schellekens’ list Schellekens
(Commun Math Phys 153:159–185, 1993). 相似文献
10.
In this paper, we prove a maximum principle for a frequency localized transport-diffusion equation. As an application, we
prove the local well-posedness of the supercritical quasi-geostrophic equation in the critical Besov spaces
\mathringB1-a¥,q{\mathring{B}^{1-\alpha}_{\infty,q}}, and global well-posedness of the critical quasi-geostrophic equation in
\mathringB0¥,q{\mathring{B}^{0}_{\infty,q}} for all 1 ≤ q < ∞. Here
\mathringBs¥,q {\mathring{B}^{s}_{\infty,q} } is the closure of the Schwartz functions in the norm of Bs¥,q{B^{s}_{\infty,q}}. 相似文献
11.
The time-dependent and time-independent CP asymmetries $
A_{CP}^{B_q^0 \to f} \left( \tau \right)
$
A_{CP}^{B_q^0 \to f} \left( \tau \right)
and $
A_{CP}^{B_q^0 \to f} \left( {\hat s} \right)
$
A_{CP}^{B_q^0 \to f} \left( {\hat s} \right)
for rare semileptonic and radiative leptonic decays of B mesons are calculated by the method of helicity amplitudes. The sensitivity of CP asymmetries to various extensions of the Standard Model that have an operator basis that is identical to the operator basis
of the Standard Model is investigated. It is shown that, by combining information about the form of the charge lepton asymmetry
A
FB
at small values of the square of the invariant dilepton mass and information about the average value of the time-dependent
CP asymmetry, one can in principle determine the relative phases of the Wilson coefficients C
7γ
, C
9V
, and C
10A
in the effective Hamiltonian for b → {d, s}ℓ+ℓ− transitions. 相似文献
12.
Gui-Jun Ding 《The European Physical Journal C - Particles and Fields》2009,64(2):297-308
The interpretation of Y(4140) as a D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} molecule is studied dynamically in the one boson exchange approach, where σ, η and φ exchange are included. Ten allowed D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} states with low spin parity are considered, and we find that the J
PC
=0++, 1+−, 0−+, 2++ and 1−−
D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} configurations are most tightly bound. We suggest that the most favorable quantum numbers are J
PC
=0++ for Y(4140) as a D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} molecule; however, J
PC
=0−+ and 2++ cannot be excluded. We propose to search for the 1+− and 1−− partners in the J/ψ
η and J/ψ
η′ final states, which is an important test of the molecular hypothesis of Y(4140) and the reasonability of our model. The 0++
B*s[`(B)]*sB^{*}_{s}\bar{B}^{*}_{s} molecule should be deeply bound; experimental search in the ϒ(1S)φ channel at Tevatron and LHC is suggested. 相似文献
13.
Zhi-Gang Wang Zhi-Cheng Liu Xiao-Hong Zhang 《The European Physical Journal C - Particles and Fields》2009,64(3):373-386
In this article, we assume that there exist scalar D*[`(D)]*{D}^{\ast}{\bar {D}}^{\ast}, Ds*[`(D)]s*{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B*[`(B)]*{B}^{\ast}{\bar {B}}^{\ast} and Bs*[`(B)]s*{B}_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states, and study their masses using the QCD sum rules. The numerical results indicate that the masses are about
(250–500) MeV above the corresponding D
*–[`(D)]*{\bar{D}}^{\ast}, D
s
*–[`(D)]s*{\bar {D}}_{s}^{\ast}, B
*–[`(B)]*{\bar{B}}^{\ast} and B
s
*–[`(B)]s*{\bar {B}}_{s}^{\ast} thresholds, the Y(4140) is unlikely a scalar Ds*[`(D)]s*{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast} molecular state. The scalar D*[`(D)]*D^{\ast}{\bar{D}}^{\ast}, Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B*[`(B)]*B^{\ast}{\bar{B}}^{\ast} and Bs*[`(B)]s*B_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states maybe not exist, while the scalar D¢*[`(D)]¢*{D'}^{\ast}{\bar{D}}^{\prime\ast}, Ds¢*[`(D)]s¢*{D}_{s}^{\prime\ast}{\bar{D}}_{s}^{\prime\ast}, B¢*[`(B)]¢*{B}^{\prime\ast}{\bar{B}}^{\prime\ast} and Bs¢*[`(B)]s¢*{B}_{s}^{\prime\ast}{\bar{B}}_{s}^{\prime\ast} molecular states maybe exist. 相似文献
14.
K. Terasaki 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):676-678
Although assigning D
s0
+(2317) to the I
3 = 0 component
of iso-triplet four-quark mesons is favored by experiments, its neutral and doubly charged partners have not yet been observed.
It is discussed why they were not observed in inclusive e
+
e
-→cˉ experiment and that they can be observed in B decays. 相似文献
15.
S. N. Gninenko M. M. Kirsanov N. V. Krasnikov V. A. Matveev 《Physics of Atomic Nuclei》2007,70(3):441-449
The SU
c
(3) ⊗ SU
L
(2) ⊗ SU
R
(2) ⊗ U(1) left-right (LR) symmetric model explains the origin of the parity violation in weak interactions and predicts the existence
of additional gauge bosons W
R
and Z′. In addition, heavy right-handed Majorana neutrino states N arise naturally within the LR symmetric model. The states N could be partners of light neutrino states, related to their nonzero masses through the seesaw mechanism. This makes the
searches for W
R
, Z′, and N interesting and important. In the framework of the minimal LR model, we study the possibility to observe signals from N and W
R
production in pp collisions after three years of running at low LHC luminosity. We show that their decay signals can be identified with a
small background, especially in the case of same-sign leptons in the final state. For the integral LHC luminosity of L
t
= 30 fb−1, the 5σ discovery of W
R
boson and heavy Majorana neutrinos N
e
with masses
up to 4 TeV and
up to 2.4 TeV, respectively, is found to be possible.
The text was submitted by the authors in English. 相似文献
16.
We analysed the process of \(B_{c}^{+}{\to } D_{s}^{+}\overline {K}^{0^{\ast } }\) using QCD factorization (QCDF) and final-state interaction (FSI) effects. First, the \(B_{c}^{+}{\to } D_{s}^{+}\overline {K}^{0^{\ast } }\) decay is calculated using QCDF method. The value found by using the QCDF method is less than the experimental value. Then we considered FSI effect as a sizable correction where the intermediate state \(D^{+^{\ast } }\pi ^{0}\) mesons via the exchange of \(K^{0}(K^{0^{\ast } })\) are produced. To consider the amplitudes of this intermediate state, the QCDF approach was used. The experimental branching ratio of \(B_{c}^{+}{\to } D_{s}^{+}\overline {K}^{0^{\ast } }\) decay is less than 0.4×10?6 and our results are (0.21±0.04)×10?7 and (0.37±0.05)×10?6 from QCDF and FSI, respectively. 相似文献
17.
Lixin Xu Jianbo Lu Yuting Wang 《The European Physical Journal C - Particles and Fields》2012,72(2):1883
In this paper, we revisit the generalized Chaplygin gas (GCG) model as a unified dark matter and dark energy model. The energy
density of GCG model is given as ρ
GCG/ρ
GCG0=[B
s
+(1−B
s
)a
−3(1+α)]1/(1+α), where α and B
s
are two model parameters which will be constrained by type Ia supernova as standard candles, baryon acoustic oscillation
as standard rulers and the seventh year full WMAP data points. In this paper, we will not separate GCG into dark matter and
dark energy parts any more as adopted in the literature. By using the Markov Chain Monte Carlo method, we find the results
a = 0.00126-0.00126- 0.00126+ 0.000970+ 0.00268\alpha=0.00126_{-0.00126- 0.00126}^{+ 0.000970+ 0.00268} and Bs = 0.775-0.0161- 0.0338+ 0.0161+ 0.0307B_{s}= 0.775_{-0.0161- 0.0338}^{+ 0.0161+ 0.0307}. 相似文献
18.
X.-H. Guo Gang Lü Z.-H. Zhang 《The European Physical Journal C - Particles and Fields》2008,58(2):223-244
In the framework of factorization we study direct CP violation in the decays of bottom hadrons containing a strange quark or a charm quark, H
b
→f
ρ
0(ω)→f
π
+
π
− (H
b
is the bottom hadron and f is the product hadron) including the effect of ρ–ω mixing. We find that the CP violating asymmetry can be enhanced greatly via the ρ–ω mixing mechanism when the invariant mass of the π
+
π
− pair is in the vicinity of the ω resonance. For the processes associated with b→d transitions, e.g.
,
, B
c
−→D
−
π
+
π
−, B
c
−→D
*−
π
+
π
−, Ξ
b
0→Λ
π
+
π
−, and Ω
b
−→Ξ
−
π
+
π
−, the maximum CP violating asymmetries can reach about −84%, while for the processes associated with b→s transitions, e.g.
,
, B
c
−→D
s
−
π
+
π
−, B
c
−→D
s
*−
π
+
π
−, Ξ
b
−→Ξ
−
π
+
π
−, and Ω
b
−→Ω
−
π
+
π
−, the CP violating asymmetries can be enhanced to about 95%. Furthermore, taking ρ–ω mixing into account we calculate the b-hadron decay branching ratios. We also discuss the possibility to observe the predicted CP violating asymmetries at the LHC. 相似文献
19.
The production of heavy quarks in heavy-ion collisions is important because it is expected to give information about high-density
QCD matter. One interesting channel of heavy quark measurements at LHC is the decay of B to J/ψ. The J/ψ mesons from this channel can be separated from the primary J/ψ (produced at collision vertex) by using the secondary vertex which is efficiently reconstructed with the CMS tracker. In
this work, the generator level results for the primary and secondary J/ψ obtained through dimuon pairs are presented for pp and PbPb collisions at $
\sqrt {s_{NN} }
$
\sqrt {s_{NN} }
= 5.5 TeV. 相似文献
20.
Combined constraints on modified Chaplygin gas model from cosmological observed data: Markov Chain Monte Carlo approach 总被引:1,自引:0,他引:1
We use the Markov Chain Monte Carlo method to investigate a global constraints on the modified Chaplygin gas (MCG) model as
the unification of dark matter and dark energy from the latest observational data: the Union2 dataset of type supernovae Ia
(SNIa), the observational Hubble data (OHD), the cluster X-ray gas mass fraction, the baryon acoustic oscillation (BAO), and
the cosmic microwave background (CMB) data. In a flat universe, the constraint results for MCG model are, Wbh2 = 0.02263+0.00184-0.00162 (1s)+0.00213-0.00195 (2s){\Omega_{b}h^{2}\,{=}\,0.02263^{+0.00184}_{-0.00162} (1\sigma)^{+0.00213}_{-0.00195} (2\sigma)}, Bs = 0.7788+0.0736-0.0723(1s)+0.0918-0.0904 (2s){B_{s}\,{=}\,0.7788^{+0.0736}_{-0.0723}(1\sigma)^{+0.0918}_{-0.0904} (2\sigma)}, a = 0.1079+0.3397-0.2539 (1s)+0.4678-0.2911 (2s){\alpha\,{=}\,0.1079^{+0.3397}_{-0.2539} (1\sigma)^{+0.4678}_{-0.2911} (2\sigma)}, B = 0.00189+0.00583-0.00756(1s)+0.00660-0.00915 (2s){B\,{=}\,0.00189^{+0.00583}_{-0.00756}(1\sigma)^{+0.00660}_{-0.00915} (2\sigma)}, and H0=70.711+4.188-3.142 (1s)+5.281-4.149(2s){H_{0}=70.711^{+4.188}_{-3.142} (1\sigma)^{+5.281}_{-4.149}(2\sigma)}. 相似文献