Isotropic coordinates for Schwarzschild black hole radiation

The isotropic coordinate system of Schwarzschild spacetime has several attractive properties similar with the Painlevé–Gullstrand coordinates. The purpose for us to choose the isotropic coordinates is to resolve the ambiguities of the tunneling picture in Hawking radiation. Based on energy conservation, we investigate Hawking radiation as massless particles tunneling across the event horizon of the Schwarzschild black hole in the isotropic coordinates. Because the amplitude for a black hole to emit particles is related to the amplitude for it to absorb, we must take into account the contribution of ingoing solution to the action, ImS=ImS_out−ImS_in. It will be shown that the imaginary part of action for ingoing particles is zero (ImS_in=0) in the Painlevé–Gullstrand coordinates, so the equation ImS=ImS_out−ImS_in is valid in both the isotropic coordinates and the Painlevé–Gullstrand coordinates.     

: Hadronic molecules in effective field theory

We consider the implications from the possibility that the recently observed state X(3872) is a meson–antimeson molecule. We write an effective Lagrangian consistent with the heavy-quark and chiral symmetries needed to describe X(3872). We explore the consequences of the assumption that X(3872) is a molecular bound state of D^*0 and mesons for the existence of bound states in the and channels.     

The new multiplet, heavy baryon mass predictions, meson–baryon universality and effective supersymmetry in hadron spectrum

The recent measurement by CDF M(Σ_b)−M(Λ_b)=192 MeV is in striking agreement with our theoretical prediction M(Σ_b)−M(Λ_b)=194 MeV. In addition, the measured splitting agrees well with the predicted splitting of 22 MeV. We point out the connection between these predictions and an effective supersymmetry between mesons and baryons related by replacing a light antiquark by a light diquark. We discuss the theoretical framework behind these predictions and use it to provide additional predictions for the masses of spin- and spin- baryons containing heavy quarks, as well as for magnetic moments of Λ_b and Λ_c.     

Discrete symmetry and CP phase of the quark mixing matrix

A simple specific pattern of the two 3×3 quark mass matrices is proposed, resulting in a prediction of the CP phase of the charged-current mixing matrix V_CKM, i.e., sin2₁(β)=0.733, which is in remarkable agreement with data, i.e., sin2₁=0.728±0.056±0.023 from Belle and sin2β=0.722±0.040±0.023 from BaBar. This pattern can be maintained by a discrete family symmetry, an example of which is D₇, the symmetry group of the heptagon.     

Near tribimaximal neutrino mixing with symmetry

The discrete subgroup Δ(27) of SU(3) has the interesting multiplication rule , which is used to obtain near tribimaximal neutrino mixing. Using present neutrino oscillation data as input, this model predicts that the effective mass m_ee measured in neutrinoless double beta decay will be 0.14 eV.     

Is the β phase maximal?

The current experimental determination of the absolute values of the CKM elements indicates that 2|V_ub/V_cbV_us|=(1−z), with z given by z=0.19±0.14. This fact implies that irrespective of the form of the quark Yukawa matrices, the measured value of the SM CP phase β is approximately the maximum allowed by the measured absolute values of the CKM elements. This is for , which implies =π/2. Alternatively, assuming that β is exactly maximal and using the experimental measurement sin(2β)=0.726±0.037, the phase γ is predicted to be γ=(π/2−β)=66.3°±1.7°. The maximality of β, if confirmed by near-future experiments, may give us some clues as to the origin of CP violation.     

Loop states in lattice gauge theory

We reformulate d-dimensional SU(2) lattice gauge theory in terms of gauge invariant loop state variables by solving the SU(2) Gauss law as well as the corresponding Mandelstam constraints. The loop states satisfying the Gauss law and the Mandelstam constraints in d dimension are explicitly constructed in terms of the SU(2) harmonic oscillator prepotential operators. We show that these mutually independent (orthonormal) loop states carry certain non-negative integer Abelian fluxes over the lattice links and are characterized by 3(d−1) gauge invariant angular momentum quantum numbers per lattice site. Thus, they provide a complete orthonormal loop basis in the physical Hilbert space of the gauge theory. Further, we derive the loop Hamiltonian and show that it counts, creates and annihilates the Abelian fluxes over the plaquettes. The generalization to SU(N) gauge group is discussed.     

A texture for neutrino oscillations and leptogenesis

In an economical system with only two heavy right-handed neutrinos, we postulate a new texture for 3×2 Dirac mass matrix m_D. This model implies one massless light neutrino and thus displays only two patterns of mass spectrum for light neutrinos, namely hierarchical or inverse-hierarchical. Both the cases can correctly reproduce all the current neutrino oscillation data with a unique prediction and for the hierarchical and the inverse-hierarchical cases, respectively, which can be tested in next generation neutrino-less double beta decay experiments. Introducing a single physical CP phase in m_D, we examine baryon asymmetry through leptogenesis. Interestingly, through the CP phase there are correlations between the amount of baryon asymmetry and neutrino oscillation parameters. We find that for a fixed CP phase, the hierarchical case also succeeds in generating the observed baryon asymmetry in our universe, plus a non-vanishing U_e3 which is accessible in future baseline neutrino oscillation experiments.     

Factorization of large-x quark distributions in a hadron

We present a factorization formula for valence quark distributions in a hadron in x→1 limit. For the example of pion, we arrive at the form of factorization by analyzing momentum flow in the leading and high-order Feynman diagrams. The result confirms the well-known 1−x scaling rule to all orders in perturbation theory, providing the nonperturbative matrix elements for the infrared divergence factors. We comment on resummation of perturbative single and double logarithms in 1−x.     

Standard Model with the additional symmetry on the lattice

An additional Z₆ symmetry hidden in the fermion and Higgs sectors of the Standard Model has been found recently [Phys. Lett. B 583 (2004) 379]. A lattice regularization of the Standard Model was constructed that possesses this symmetry. In [Yad. Fiz. (2005)] we have reported our results on the numerical simulation of the electroweak sector of the model. In this Letter we report our results on the numerical simulation of the full (SU(3)SU(2)U(1)) model. The phase diagram of the model has been investigated using static quark and lepton potentials. Various types of monopoles have been constructed. Their densities appear to be sensitive to the phase transition lines. Differences between the realizations of the Standard Model which do or do not possess the mentioned Z₆ symmetry, are discussed.     

Large angle hadron correlations from medium-induced gluon radiation

Final state medium-induced gluon radiation in ultradense nuclear matter is examined and shown to favor large angle emission when compared to vacuum bremsstrahlung due to the suppression of collinear gluons. Perturbative expression for the contribution of its hadronic fragments to the back-to-back particle correlations is derived. It is found that in the limit of large jet energy loss gluon radiation determines the yield and angular distribution of dihadrons to high transverse momenta p_T2 of the associated particles. Clear transition from enhancement to suppression of the away-side hadron correlations is established at moderate p_T2 and its experimentally accessible features are predicted versus the trigger particle momentum p_T1.     

Evolution of coupled classical fields

We study the evolution of the coupled scalar and fermion fields within the classical field theory. We examine the case of N coupled fields in (1+3)-dimensional space. The general expressions for the fields distributions are obtained. The particular case of two fields in (1+1)-dimensional space is carefully studied. We obtain the expressions for the averaged fields intensities and show that in the relativistic limit they are similar to the usual transition probabilities formulae of neutrino oscillations.     

Neutron β-decay, Standard Model and cosmology

The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. The neutron lifetime recently obtained, 878.5±0.7_stat±0.3_sys s, is the most accurate one to date. The new result for the neutron lifetime differs from the world average value by 6.5σ. The impact of the new result on testing of Standard Model and on data analysis for the primordial nucleosynthesis model is scrutinized.     

“T-odd effects” in unpolarized Drell–Yan scattering

We consider the leading twist “T-odd” contributions as the dominant source of the cos2 azimuthal asymmetry in unpolarized di-lepton production in Drell–Yan scattering. This asymmetry contains information on the distribution of quark transverse spin in an unpolarized proton. In a parton-spectator framework we estimate these asymmetries at 50 GeV center of mass energy. This azimuthal asymmetry is interesting in light of proposed experiments at GSI, where an anti-proton beam is ideal for studying the transversity properties of quarks due to the dominance of valence quark effects.     

Measurements of decays into and

Based on a sample of 5.8×10⁷ J/ψ events taken with the BESII detector, the branching fractions of J/ψ→2(π⁺π⁻)η and J/ψ→3(π⁺π⁻)η are measured for the first time to be (2.26±0.08±0.27)×10⁻³ and (7.24±0.96±1.11)×10⁻⁴, respectively.     

production in exclusive B decays

Production of f₀(1710), a theoretical endeavor of pure scalar glueball state, is studied in detail from exclusive rare B decay within the framework of perturbative QCD. The branching fraction for is estimated to be about 8×10⁻⁶, while for it is smaller by roughly an order of magnitude. With the accumulation of almost 1 billion pairs from the BaBar and Belle experiments to date, hunting for a scalar glueball via these rare decay modes should be attainable.     

Gauged supersymmetric σ-models and soft breaking terms

Supersymmetric nonlinear σ-models in four dimensions with D-term potentials can sometimes have a singular metric. As the kinetic terms of scalar fields and their chiral fermionic partners are determined by this metric, it follows that their kinetic energy vanishes in the vacuum. In previous work we have shown for a simple model that this degeneracy of the sigma-model metric can be lifted by soft supersymmetry breaking terms. In this Letter I introduce soft breaking terms in more realistic models based on SO(10) and E₆ and compute their resulting mass spectra.     

Vertex ring-indexed Lie algebras

Infinite-dimensional Lie algebras are introduced, which are only partially graded, and are specified by indices lying on cyclotomic rings. They may be thought of as generalizations of the Onsager algebra, but unlike it, or its sl(n) generalizations, they are not subalgebras of the loop algebras associated with sl(n). In a particular interesting case associated with sl(3), their indices lie on the Eisenstein integer triangular lattice, and these algebras are expected to underlie vertex operator combinations in CFT, brane physics, and graphite monolayers.     

QCD sum rule study of the masses of light tetraquark scalar mesons

We study the low-lying scalar mesons of light u, d, s flavors in the QCD sum rule. Having all possible combinations of tetraquark currents in the local form, QCD sum rule analysis has been carefully performed. We found that using the appropriate tetraquark currents, the masses of σ, κ, f₀ and a₀ mesons appear in the region of 0.6–1 GeV with the expected ordering. The results are compared with that of the conventional currents, where the masses are considerably larger.     

Conditional observability

For a quantum Hamiltonian H=H(λ), the observability of the energies E may be robust (whenever all E are real at all λ) or, otherwise, conditional. Using a pseudo-Hermitian family of N-state chain models H=H^(N)(λ) we discuss some generic properties of conditionally observable spectra.