共查询到20条相似文献,搜索用时 0 毫秒
1.
《中国物理C(英文版)》2017,(4)
The masses of the three generations of charged leptons are known to completely satisfy Koide's mass relation,but the question remains of whether such a relation exists for neutrinos.In this paper,by considering the seesaw mechanism as the mechanism generating tiny neutrino masses,we show how neutrinos satisfy Koide's mass relation,on the basis of which we systematically give exact values of both left-and right-handed neutrino masses. 相似文献
2.
When the fourth generation of quarks have sufficiently small mixing with ordinary standard-model quarks, the hadrons made up from these quarks can be long-lived enough. We analyze the (1/2)+ baryon states containing fourth-generation quarks and standard-model quarks, i.e. the charm or bottom quarks, in the QCD sum rules approach. Considering the perturbative and two gluon condensate contributions in the calculation, we give the numerical results of the masses and pole residues. 相似文献
3.
Recent Tevatron exclusion interval of the masses of Higgs boson considerably reduces in case of the light quasistable fourth generation neutral lepton. 相似文献
4.
The effect of strong magnetic field on the bulk properties of quark matter is reinvestigated takingu, d ands-quarks as well as electrons in the presence of magnetic field. Here the bag pressure is chosen such that in the absence of
magnetic field and at zero temperature the binding energy of theuds-system is <930 MeV while that ofud-system is greater than 940 MeV. It is observed that the equation of state changes significantly in a strong magnetic field.
At finite temperature the electron chemical potential varies between 6 and 50 MeV. Thus the expansion of thermodynamical quantities
in powers ofT/(Μ
i
2
-M
v
(i)2
)1/2 is valid only up to few MeV. For high temperatures ∼40 MeV the exact integral expressions are to be taken. 相似文献
5.
The suggestion made by Lipkin regarding the quark masses and magnetic moments of baryons is examined in the context of the
variable pressure bag model. We find that the exact agreement obtained by Lipkin between theory and experiment in the case
ofμ(Λ) cannot be considered accidental, contrary to the scepticism expressed by Minami. 相似文献
6.
We find the classical solutions of a model of quark confinement defined by the vanishing of colour currents. Both plane-wave
type of solutions extending all over space as well as string-type of solutions confined to restricted regions of space are
found. 相似文献
7.
The influence of chromomagnetic hyperfine interaction onB andT hadrons is studied. The colour magnetic moments are related to the hyperfine splittings of hadrons. 相似文献
8.
9.
We calculate the effects of finite quark masses for the semileptonic and nonleptonic decays of charmed particles. The total lifetimes of charmed particles are not sensitive to the masses of the quarks in the final state. However the semileptonic branching ratios changes considerably. Using conventional constituent quark masses, one expect e.g. Be(D+)≈ 21%. The brancing ratios and lifetimes of the charmed particles are estimated, taking into account the annihilation hypothesis. 相似文献
10.
G. R. Boroun 《中国物理C(英文版)》2021,45(6):063105-063105-10
In this article,we consider the ratio of structure functions for heavy quark pair production at low values of The importance of this ratio for charm and beauty pair production is examined according to the Hadron Electron Ring Accelerator(HERA) data.The behavior of these ratios is considered due to the hard pomeron behavior of the gluon distribution function.The results are in good agreement with the HERA data.Expanding this data to the range of new energies underscores the importance of these measurements for heavy quarks.The ratio of charm and beauty structure functions at the proposed Large Hadron electron Collider(LHeC) is considered as a function of invariant center-of-mass energy.For top pair production this ratio is extracted with known kinematics of the LHeC and Future Circular Collider electron-hadron(FCC-eh) colliders.Comparison of the results obtained for the ratio of top structure functions in LHeC and FCC-eh are proportional to the specified inelasticity y range. 相似文献
11.
Within a phenomenological quasiparticle model, the quark mass and temperature dependence of the QCD equation of state is discussed and compared with lattice QCD results. Different approximations for the quasiparticle dispersion relations are employed, scaling properties of the equation of state with quark mass and deconfinement temperature are investigated and a continuation to asymptotically large temperatures is presented. 相似文献
12.
Heavy quarks play an important role in probing the properties of strongly interacting quark-gluon plasma(QGP)created in ultra-relativistic heavy-ion collisions.We study the interactions of single heavy(charm)quarks and correlated charm and anticharm(ccˉ)quark pairs with the medium constituents of QGP by performing fireball+Langevin simulations of the pertinent Brownian motion with elastic collisions.Besides studying the traditional observables,the nuclear modification factor and the elliptic flow of single heavy quarks in QGP for different thermal relaxation rates,we also study the broadening of the azimuthal correlations of charm and anticharm quark pairs in the QGP medium for different relaxation rates and transverse momenta classes.We quantified the smearing of ccˉpair azimuthal correlations with an increasing thermal relaxation rate:while the(nearly)back-to-back correlations among ccˉpairs are almost completely washed out at low transverse momentum(pT),these correlations at high pT largely survive the pair diffusion.This provides a novel observable for diagnosing the properties of QGP. 相似文献
13.
The current quark mass model is adopted to study the phase transition of two-flavor quark matter to more stable three-flavor quark matter in the whole core of a supernova. It shows that the timescale of the process is shorter than 10-8 seconds, that the u- and d-quark masses can be neglected completely in this model, and that the temperature and the total neutrino energies in the core after the conversion increase nearly by 40% and 20% on the average compared with former results, respectively. The last result can further enhance the probability of success for a supernova explosion significantly. 相似文献
14.
The current quark mass model is adopted to study the phase transition of two-flavor quark matter to more stable three-flavor quark matter in the whole core of a supernova. It shows that the timescale of the process is shorter than 10-8 seconds, thatthe u- and d-quark masses can be neglected completely in this model, and that the temperature and the total neutrino energies in the core after the conversion increase nearly by 40% and 20% on the average compared with former results, respectively. The last result can further enhance the probability of success for a supernova explosion significantly. 相似文献
15.
16.
17.
Flavour symmetry breaking is introduced in the approximate formula for quark mass reported earlier. We use SLAC-MIT as well
as NMC data to estimate the up, down and strange quark masses from structure functions. Using the approximateQ
2 evolutions of Altarelli-Parisi equations, we also estimate its perturbative and nonperturbative components. 相似文献
18.
The top quark mass and the flavour mixing are studied in the context of a seesaw model of quark masses based on the gauge group SU(2)L × SU(2)R × U(1). Six isosinglet quarks are introduced to give rise to the mass hierarchy of ordinary quarks. In this scheme, we reexamine a mechanism for the generation of the top quark mass. It is shown that, in order to prevent the seesaw mechanism to act for the top quark, the mass parameter of its isosinglet partner must be much smaller than the breaking scale of SU(2)R. As a result the fourth lightest up quark must have a mass of the order of the breaking scale of SU(2)R, and a large mixing between the right-handed top quark and its singlet partner occurs. We also show that this mechanism is compatible with the mass spectrum of light quarks and their flavour mixing. 相似文献
19.
Carolina Arbeláez A. E. Cárcamo Hernández Sergey Kovalenko Ivan Schmidt 《The European Physical Journal C - Particles and Fields》2017,77(6):422
We propose a predictive inert two-Higgs doublet model, where the standard model (SM) symmetry is extended by \(S_{3}\otimes Z_{2}\otimes Z_{12}\) and the field content is enlarged by extra scalar fields, charged exotic fermions and two heavy right-handed Majorana neutrinos. The charged exotic fermions generate a non-trivial quark mixing and provide one-loop-level masses for the first- and second-generation charged fermions. The masses of the light active neutrinos are generated from a one-loop-level radiative seesaw mechanism. Our model successfully explains the observed SM fermion mass and mixing pattern. 相似文献
20.
《Physics letters. [Part B]》1988,214(1):120-122
It is shown by numerical calculation that the best fit of the Fritzsch matrix to present data is found for values of the top-quark mass between 30 and 60 GeV, depending on the value adopted for the strange-quark mass. The value of mt that produces the best fit is very close to the geometrical scaling prediction of mt = mb(mc/ms) for current-quark masses. The residuals of the fit obey a surprising scaling rule, being functions of msmt rather than of ms and mt separately. 相似文献