12913086
Singlet fermionic dark matter
We propose a renormalizable model of a fermionic dark matter by introducing a gauge singlet Dirac fermion and a real singlet scalar. The bridges between the singlet sector and the standard model sector are only the singlet scalar interaction terms with the standard model Higgs field. The singlet fermion couples to the standard model particles through the mixing between the standard model Higgs and singlet scalar and is naturally a weakly interacting massive particle (WIMP). The measured relic abundance can be explained by the singlet fermionic dark matter as the WIMP within this model. Collider implication of the singlet fermionic dark matter is also discussed. Predicted is the elastic scattering cross section of the singlet fermion into target nuclei for a direct detection of the dark matter. Search of the direct detection of the dark matter provides severe constraints on the parameters of our model.
16221979
POLARIZATION EFFECTS ON THE E+E- W+W- PROCESS WITH LARGE EXTRA DIMENSIONS
Abstract We study large extra dimension effects on the polarizations of the W pair and electron beam at the e + e − → W + W − process. It is shown that the measurements of the cross section for transversely polarized W pair with the right-handed electron beam remarkably enhance the possibilities to see the low scale quantum gravity effects. Higher Linear Collider bounds on the string scale in this model can be obtained by using the left-handed electron beam.
15426025
Large extra dimension effects on the spin configuration of the top quark pair at e + e − colliders
Large extra dimension effects on the spin configuration of the top quark pair at the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}t\overline{t}$ process are studied. It is shown that the TeV scale quantum gravity effects cause significant deviations from standard model (SM) predictions for the spin configuration in the off-diagonal basis: they lead to substantial cross sections of the like-spin states of the top quark pair, which vanish in the SM; they weaken the pure dominance of the processes, the up-down (down-up) spin states for the left-handed (right-handed) beam. In addition it is shown that the angular cut $\ensuremath{-}0.5l\mathrm{cos}\ensuremath{\theta}l0$ is very effective to determine the sign of the quantum gravity corrections.
17539215
Implications of the recent CERN LEP data on nonuniversal interactions with the precision electroweak tests
We explore the nonuniversal interaction effects in terms of the precision variables epsilons with the recent CERN LEP data reported by the Electroweak Working Group. The epsilon variables with the nonuniversal interactions are calculated and constrained by the experimental ellipses in the {epsilon}{sub 1}{endash}{epsilon}{sub b}, {epsilon}{sub 2}{endash}{epsilon}{sub b}, and {epsilon}{sub 3}{endash}{epsilon}{sub b} planes. We find that the new data enable us to make a stringent test on the correction to Z{r_arrow}b{bar b} vertex. The {epsilon}{sub b} variable is sensitive to the Zb{bar b} couplings and thus plays a major role to give constraints on the nonuniversal interaction effects. Upon imposing the new data on {epsilon}{sub b}, we have the allowed range of the model parameter {kappa}{sub L}=0.0063{plus_minus}0.0030 at 1-{sigma} level with m{sub t}=175 GeV. Along with the minimal contact term, we predict the new physics scale {Lambda}{approximately} 1.6 TeV. By combining the experimental results from all planes we obtain the allowed range of {kappa}{sub L}: 0.003{lt}{kappa}{sub L}{lt}0.010 at 95{percent} C.L. {copyright} {ital 1997} {ital The American Physical Society}
16963420
Evolution equation for the heavy quark distribution function in the parton model approach
We explore the perturbative QCD corrections to the inclusive semileptonic decays of $B$ mesons. In inclusive $B$ decay processes the parton picture works well and the scaling feature manifests because the mass of $b$ quark is larger than the QCD scale. Due to this property, the decay rate may be expressed by a single structure function describing the light-cone distribution of $b$ quark apart from the kinematic factor. We derive a $q^2$ evolution equation for the distribution function, which violates the scaling property through the Altarelli-Parisi type approach. The evolution equation is numerically solved and its phenomenological implications are also discussed.
14611917
Polarization effects on W boson pair productions with the extra neutral gauge boson at the e^+ e^- Linear Collider
We perform the comprehensive analysis of the polarization effects on the e^+e^- -> W^+W^- process in the presence of the extra neutral gauge boson at the LC energies. Consideration of the polarizations of the produced W bosons and the beam polarizations provides substantial enhancements of the sensitivity to the Z-Z' mixing angles in various models and the asymmetry variables also give the strict constraints on the mixing angles. We find that the \chi-model and the left-right model get the strict constraint from \sigma_{LL}^{unpol} while the \psi-model and the \eta-model from the beam polarization asymmetry.
14906179
Chern-Simons solitons, chiral model, and (affine) Toda model on noncommutative space
We consider the Dunne-Jackiw-Pi-Trugenberger model of a U(N) Chern-Simons gauge theory coupled to a nonrelativistic complex adjoint matter on noncommutative space. Soliton configurations of this model are related the solutions of the chiral model on noncommutative plane. A generalized Uhlenbeck's uniton method for the chiral model on noncommutative space provides explicit Chern-Simons solitons. Fundamental solitons in the U(1) gauge theory are shaped as rings of charge and spin − where the Chern-Simons level should be an integer upon quantization. Toda and Liouville models are generalized to noncommutative plane and the solutions are provided by the uniton method. We also define affine Toda and sine-Gordon models on noncommutative plane. Finally the first order moduli space dynamics of Chern-Simons solitons is shown to be trivial.
118209688
ABCD of 3d ${\cal N}=8$ and 4 Superconformal Field Theories
We argue the equivalence between the infrared conformal field theory of the 3d $\CN=8$ supersymmetric Yang-Mills theories of ABCD ($U(N), SO(2N+1), Sp(2N), O(2N)$) gauge groups and the ABJ(M) theories of $U(N)_k\times U(\tilde N)_{-k}$ for $k=1,2$. We support this duality by comparing the superconformal index of the IR limit of these super Yang-Mills theories and that of those ABJ(M) models. Especially we find the match between two indices of (mirror dual of) the $\CN=8$ U(N) SYM and of $U(N)_1\times U(N)_{-1}$ ABJM model. Also we take large $N$ limit of ABCD super Yang-Mills theories with additional fundamental hyper-multiplets and infer the large N limit of $\CN=8$ ABCD theories themselves, finding the expected gravitational duals. With the additional input on finite N, we argue the equivalence of Yang-Mills and ABJ(M) theories for all N. We further explore similar dualities to Chern-Simons matter theories for $\CN=4$ Yang-Mills theories related by mirror symmetry.
14514990
1/16-BPS black holes and giant gravitons in the AdS5 × S5 Space
We explore 1/16-BPS objects of type IIB string theory in AdS5 ? S5. First, we consider supersymmetric AdS5 black holes, which should be 1/16-BPS and have a characteristic that not all physical charges are independent. We point out that the Bekenstein-Hawking entropy of these black holes admits a remarkably simple expression in terms of (dependent) physical charges, which suggests its microscopic origin via certain Cardy or Hardy-Ramanujan formula. We also note that there is an upper bound for the angular momenta given by the electric charges. Second, we construct a class of 1/16-BPS giant graviton solutions in AdS5 ? S5 and explore their properties. The solutions are given by the intersections of AdS5 ? S5 and complex 3 dimensional holomorphic hyperspaces in 1+5, the latter being the zero loci of three holomorphic functions which are homogeneous with suitable weights on coordinates. We investigate examples of giant gravitons, including their degenerations to tensionless strings.
122069269
Ground state of high-density matter
Abstract It is shown that if an upper bound to the false vacuum energy of the electroweak Higgs potential is satisfied, the true ground state of high-density matter is not nuclear matter, or even strange-quark matter, but rather a non-topological soliton where the electroweak symmetry is exact and the fermions are massless. We examine this possibility in the standard SU(3) C ⊗ SU(2) L ⊗ U(1) Y model. The bound to the false vacuum energy is satisfied only for a narrow range of the Higgs boson masses in the minimal electroweak model (within a few eV of its minimum allowed value of 6.6 GeV), and a somewhat wider range for electroweak models with a non-minimal Higgs sector.
119342958
Anomalies and effective lagrangians of superconducting cosmic strings
We study the effective lagrangians of superconducting cosmic strings and the underlying anomaly structure leading to various effects. We show that fermionic superconducting cosmic (Nielsen-Olesen) strings arise as a consequence of a mixed anomaly of the form E · B′ where E is the electromagnetic field strength and B′ the core flux of the string. We show how this controls superconductivity, the index theorems, topological mass terms on domain walls, and string-axion interactions. We contrast this to global strinfs with Chern-Simons currents.