15933925
Phenomenology of a supersymmetric model for fermion mass hierarchy
Some phenomenological aspects of a supersymmetric model for fermion mass hierarchy proposed previously are discussed. It is required that the lepton universality violation is near to its current experimental bound. The lepton number violation decay modes τ→2eμ and 3μ maybe observable in the near future. The Majorana mass of electron-neutrino is predicted to be about 0.1 eV. The fine-tuning problem is discussed.
119384069
Supersymmetry for Fermion Masses
It is proposed that supersymmetry (SUSY) maybe used to understand fermion mass hierarchies. A family symmetry Z_{3L} is introduced, which is the cyclic symmetry among the three generation SU(2) doublets. SUSY breaks at a high energy scale ~ 10^{11} GeV. The electroweak energy scale ~ 100 GeV is unnaturally small. No additional global symmetry, like the R-parity, is imposed. The Yukawa couplings and R-parity violating couplings all take their natural values which are about (10^0-10^{-2}). Under the family symmetry, only the third generation charged fermions get their masses. This family symmetry is broken in the soft SUSY breaking terms which result in a hierarchical pattern of the fermion masses. It turns out that for the charged leptons, the tau mass is from the Higgs vacuum expectation value (VEV) and the sneutrino VEVs, the muon mass is due to the sneutrino VEVs, and the electron gains its mass due to both Z_{3L} and SUSY breaking. The large neutrino mixing are produced with neutralinos playing the partial role of right-handed neutrinos. |V_{e3}| which is for nu_e-nu_{tau} mixing is expected to be about 0.1. For the quarks, the third generation masses are from the Higgs VEVs, the second generation masses are from quantum corrections, and the down quark mass due to the sneutrino VEVs. It explains m_c/m_s, m_s/m_e, m_d>m_u and so on. Other aspects of the model are discussed.
118790054
Phenomenological aspects of R-parity violating supersymmetry with a vectorlike extra generation
Phenomenological analysis to the R-parity violating supersymmetry with a vectorlike extra generation is performed in detail. It is found that, via the trilinear couplings, the correct neutrino spectrum can be obtained. The Higgs mass rises to 125 GeV by new up-type Yukawa couplings of vectorlike quarks with no need of very heavy superpartners. Phenomena of new heavy fermions at LHC are predicted. DOI: 10.1103/PhysRevD.87.075012
117463737
A Supersymmetric model with the gauge symmetry SU(3)(1) x SU(2)(1) x U(1)(1) x SU(3)(2) x SU(2)(2) x U(1)(2)
A supersymmetric model with two copies of the Standard Model gauge groups is constructed in the gauge mediated supersymmetry breaking scenario. The supersymmetry breaking messengers axe in a simple form. The Standard Model is obtained after first step gauge symmetry breaking. In the case of one copy of the gauge interactions being strong, a scenario of electroweak symmetry breaking is discussed, and the gauginos are generally predicted to be heavier than the sfermions.
14586429
QCD sum rule analysis for the Lambda(b)->Lambda(c) semileptonic decay
Abstract The 1 m c and 1 m b corrections to the Λ b → Λ c semileptonic decay are analyzed by QCD sum rules. Within the framework of heavy quark effective theory, the subleading baryonic Isgur-Wise function of Λ b → Λ c has been calculated. It is shown that the corrections due to the 1 m Lagrangian insertion are negligibly small. The sizable 1 m Q effect to the decay lies only in the weak current. The decay spectrum and the branching ratio are given.
119216988
LHCb $\bigtriangleup A_{CP}$ of $D$ Meson and R-Parity Violation
LHCb collaboration has recently announced a measurement of the difference of time-integrated CP asymmetries between $D\rightarrow K^+K^-$ and $D \rightarrow \pi^+\pi^-$. This result provides the evidence of large direct CP violation in $D$ meson and reveals some important implications on underlying new physics. It is shown that the direct CP violation in $D$ meson can be enhanced by R-parity violating supersymmetry, while CP violations in $K$ and $B$ mesons are suppressed by this new physics, which is in consistence with previous experiments. Constraints on the model parameters and some consequences are also discussed.
1482312
Strongly interacting Higgs sector without technicolor
Simulation results are presented on Higgs mass calculations in the spontaneously broken phase of the Higgs sector in the minimal Standard Model with a higher derivative regulator. A heavy Higgs particle is found in the TeV mass range in the presence of a complex conjugate ghost pair at higher energies. The ghost pair evades easy experimental detection. As a finite and unitary theory in the continuum, this model serves as an explicit and simple example of a strongly interacting Higgs sector without technicolor.
115174219
D-branes and Azumaya noncommutative geometry: From Polchinski to Grothendieck
In this continuation of (L-Y3) (arXiv:0709.1515 (math.AG)), (L-L-S-Y) (arXiv:0809.2121 (math.AG)), (L-Y4) (arXiv:0901.0342 (math.AG)), (L-Y5) (arXiv:0907.0268 (math.AG)), and (L-Y6) (arXiv:0909.2291 (math.AG)), we give an overview of the posted part of the project and then take it as background to introduce Azumaya noncommutative C ∞ -manifold and the four aspects of morphisms therefrom to a projective complex manifold. This gives us then a description of supersymmetric D-branes of A-type in a Calabi-Yau manifold along the line of the Polchinski-Grothendieck Ansatz. The notion of Kahler differentials and their tensors for an Azumaya noncommutative space are introduced. Donaldson's picture of Lagrangian and special Lagrangian submanifolds as selected from the zero-locus of a moment-map on a related space of maps can be merged into the setting of morphisms from Azumaya man- ifolds with a fundamental module. As a pedagogical toy model for illustration, we study D-branes of A-type in a Calabi-Yau torus. Simple as it is, it reveals already several features of D-branes of A-type, including their assembling/disassembling. The short-vs.-long string wrapping behavior of matrix-strings in the string-theory literature can be produced in this context as well. In addition to the previous comparison with stringy works made, the 4th theme (subtitled: "Gomez-Sharpe vs. Polchinski-Grothendieck") of Sec. 2.4 is to be read with the work (G-Sh) (arXiv:hep-th/0008150), while the 2nd theme (subtitled: "Donagi- Katz-Sharpe vs. Polchinski-Grothendieck") of Sec. 4.2 is to be read with the work (D-K-S) (arXiv:hep-th/0309270). Sec. 4.3, though not yet ready to be subtitled "Denef vs. Polchinski- Grothendieck", is to be read with the work (De) (arXiv:hep-th/0107152). Some directly related string-theory remarks are added to the end of each section.
15925356
A heavy Higgs particle in the TeV mass range
Abstract The first simulation results are presented on Higgs mass calculations in the spontaneously broken phase of the Higgs sector in the minimal Standard Model with higher derivative regulator. A heavy Higgs particle is found in the TeV mass range in the presence of a complex conjugate ghost pair at higher energies. The ghost pair evades easy experimental detection and a nonperturbative reinterpretation of the triviality Higgs mass bound becomes necessary.
16224921
On K3-Thurston 7-manifolds and their deformation space: A case study with remarks on general K3T and M-theory compactification
M-theory suggests the study of 11-dimensional space-times compactified on some 7-manifolds. From its intimate relation to superstrings, one possible class of such 7-manifolds are those that have Calabi-Yau threefolds as boundary. In this article, we construct a special class of such 7-manifolds, named as {\it K3-Thurston} (K3T) 7-manifolds. The factor from the K3 part of the deformation space of these K3T 7-manifolds admits a K\"{a}hler structure, while the factor of the deformation space from the Thurston part admits a special K\"{a}hler structure. The latter rings with the nature of the scalar manifold of a vector multiplet in an N=2 $d=4$ supersymmetric gauge theory. Remarks and examples on more general K3T 7-manifolds and issues to possible interfaces of K3T to M-theory are also discussed.
20143159
Measurements of ultracold-neutron lifetimes in solid deuterium.
We present the first measurements of the survival time of ultracold neutrons (UCNs) in solid deuterium (SD2). This critical parameter provides a fundamental limitation to the effectiveness of superthermal UCN sources that utilize solid ortho-deuterium as the source material. These measurements are performed utilizing a SD2 source coupled to a spallation source of neutrons, providing a demonstration of UCN production in this geometry and permitting systematic studies of the influence of thermal up-scatter and contamination with para-deuterium on the UCN survival time.