119238978
Minimal gauge origin of baryon triality and flavorful signatures at the LHC
Abstract Baryon triality ( B 3 ) is a Z 3 discrete symmetry that can protect the proton from decay. Although its realization does not require supersymmetry, it is particularly appealing in the supersymmetry as an alternative to the popular R-parity. We discuss the issues in gauging B 3 , and present the minimal supersymmetric model with B 3 as the remnant discrete symmetry of a TeV scale U ( 1 ) gauge symmetry. A flavor-dependent U ( 1 ) charge is necessary to achieve this, and it results in very distinguishable and flavorful predictions for the LHC experiments. We find a complementarity between a 2-lepton sneutrino resonance and a 4-lepton Z ′ resonance in the supersymmetry search when a certain condition is satisfied. In addition, we introduce baryon tetrality ( B 4 ), which would play an equivalent role if there are four fermion generations.
119280824
Four-lepton resonance at the Large Hadron Collider
New physics models admit the interesting possibility of a Z{sup '} weak boson associated with an extra U(1) gauge symmetry and a Higgs boson that is heavy enough to decay into a pair of Z bosons. Then Z{sup '} production and decay via Z{sup '}->ZH->ZZZ has a distinctive LHC signal that is nearly background-free and reconstructs the H and Z{sup '} masses and widths. The Z{sup '} decay to 3 pairs of leptons is especially distinctive. The ZH decay mode exists even if the Z{sup '} is decoupled from leptons, which motivates an independent 6-lepton resonance search regardless of the dilepton search results.
118614634
Dark side of Higgs diphoton decays and muon g − 2
We propose that the LHC hints for a Higgs diphoton excess and the muon g-2 (g_mu-2) discrepancy between theory and experiment may be related by vector-like "leptons" charged under both U(1)_Y hypercharge and a "dark" U(1)_d. Quantum loops of such leptons can enhance the Higgs diphoton rate and also generically lead to U(1)_Y - U(1)_d kinetic mixing. The induced coupling of a light U(1)_d gauge boson Z_d to electric charge can naturally explain the measured g_mu-2. We update Z_d mass and coupling constraints based on comparison of the electron g-2 experiment and theory, and find that explaining g_mu-2 while satisfying other constraints requires Z_d to have a mass ~ 20-100 MeV. We predict new Higgs decay channels gamma Z_d and Z_d Z_d, with rates below the diphoton mode but potentially observable. The boosted Z_d -> e+e- in these decays would mimic a promptly converted photon and could provide a fraction of the apparent diphoton excess. More statistics or a closer inspection of extant data may reveal such events.
119235421
Gauged B-x(i)L origin of R parity and its implications
Abstract Gauged B − L is a popular candidate for the origin of the conservation of R parity, i.e. R = ( − ) 3 B + L + 2 j , in supersymmetry, but it fails to forbid the effective dimension-five terms arising from the superfield combinations Q Q Q L , u c u c d c e c , and u c d c d c N c , which allow the proton to decay. Changing it to B − x i L , where x e + x μ + x τ = 3 (with x i ≠ 1 ) for the three families, would forbid these terms while still serving as a gauge origin of R parity. We show how this is achieved in two minimal models with realistic neutrino mass matrices, and discuss their phenomenological implications.
14087471
Generalized lepton number and dark left-right gauge model
In a left-right gauge model of particle interactions, the left-handed fermion doublet $(\ensuremath{\nu},e{)}_{L}$ is connected to its right-handed counterpart $(n,e{)}_{R}$ through a scalar bidoublet so that ${e}_{L}$ pairs with ${e}_{R}$, and ${\ensuremath{\nu}}_{L}$ with ${n}_{R}$ to form mass terms. Suppose the latter link is severed without affecting the former, then ${n}_{R}$ is not the mass partner of ${\ensuremath{\nu}}_{L}$, and as we show in this paper, becomes a candidate for dark matter which is relevant for the recent PAMELA and ATIC observations. We accomplish this in a specific nonsupersymmetric model, where a generalized lepton number can be defined, so that ${n}_{R}$ and ${W}_{R}^{\ifmmode\pm\else\textpm\fi{}}$ are odd under $R\ensuremath{\equiv}(\ensuremath{-}1{)}^{3B+L+2j}$. Fermionic leptoquarks are also predicted.
118567798
Long-range interaction effects on neutrino oscillation
Motivated by the recent anomaly in the muon neutrino and anti-muon neutrino disappearance experiments, we consider a long-range interaction with an extremely light gauge boson and extraordinarily weak coupling. A long-range interaction, consistent with current bounds, could have very pronounced effects on atmospheric neutrino disappearance that will be studied with the IceCube DeepCore array, currently in operation, and can have a significant effect on future high-precision long-baseline oscillation experiments. This invited talk was based on the paper with Hooman Davoudiasl and William Marciano [1].
9421064
Characteristics of QCD phase transitions in an extended Skyrme model on S**3
We study the characteristics of the QCD phase transitions in dense hadronic matter using the Skyrme model constructed on S^3. We find numerically the localized solutions on $S^3$ using the extended Skyrme model which implements correctly the scale symmetry of QCD. The transition from the localized phase to the delocalized phase is found to be of first order at the critical radius of the hypersphere, $L_c$. The chiral restoration and the gluon decondensation also take place at the same critical size.
16632385
Supersymmetric codimension-two branes and U(1)R mediation in 6D gauged supergravity
We construct a consistent supersymmetric action for brane chiral and vector multiplets in a six-dimensional chiral gauged supergravity. A nonzero brane tension can be accommodated by allowing for a brane-localized Fayet-Iliopoulos term proportional to the brane tension. When the brane chiral multiplet is charged under the bulk U(1)R, we obtain a nontrivial coupling to the extra component of the U(1)R gauge field strength and a singular scalar self-interaction term. Dimensionally reducing to 4D on a football supersymmetric solution, we discuss the implication of such interactions for obtaining the U(1)R D-term in the 4D effective supergravity. By assuming the bulk gaugino condensates and nonzero brane F- and/or D-term for the uplifting potential, we have all the moduli stabilized with a vanishing cosmological constant. The brane scalar with nonzero R charge then gets a soft mass of order the gravitino mass. The overall sign of the soft mass squared depends on the sign of the R charge as well as whether the brane F- or D-term dominates.
204934408
Gravity in the Einstein-Gauss-Bonnet Theory with the Randall-Sundrum Background
We obtain the full 5D graviton propagator in the Randall-Sundrum model with the Gauss-Bonnet interaction. From the decomposition of the graviton propagator on the brane, we show that localization of gravity arises in the presence of the Gauss-Bonnet term. We also obtain the metric perturbation for observers on the brane with considering the brane bending and compute the amplitude of one massless graviton exchange. For the positive definite amplitude or no ghost states, the sign of the Gauss-Bonnet coefficient should be negative in our convention, which is compatible with string amplitude computations. In that case, the ghost-free condition is sufficient for obtaining the Newtonian gravity. For a vanishing Gauss-Bonnet coefficient, the brane bending allows us to reproduce the correct graviton polarizations for the effective 4D Einstein gravity.
92983543
Dark matter, {mu} problem, and neutrino mass with gauged R symmetry
We show that the {mu} problem and the strong CP problem can be resolved in the context of the gauged U(1){sub R} symmetry, realizing an automatic Peccei-Quinn symmetry. In this scheme, right-handed neutrinos can be introduced to explain small Majorana or Dirac neutrino mass. The U(1){sub R} D-term mediated supersymmetry (SUSY) breaking, called the U(1){sub R} mediation, gives rise to a specific form of the flavor-conserving superpartner masses. For the given solution to the {mu} problem, electroweak symmetry breaking condition requires the superpartners of the standard model at low energy to be much heavier than the gravitino. Thus, the dark matter candidate can be either gravitino or right-handed sneutrino. In the Majorana neutrino case, only gravitino is a natural dark matter candidate. On the other hand, in the Dirac neutrino case, the right-handed sneutrino can be also a dark matter candidate as it gets mass only from SUSY breaking. We discuss the non-thermal production of our dark matter candidates from the late decay of stau and find that the constraints from the big bang nucleosynthesis can be evaded for a TeV-scale stau mass.
1203139
Gauge coupling unification in a 6D SO(10) orbifold GUT
Abstract We consider the gauge coupling running in a six-dimensional SO ( 10 ) orbifold GUT model. The bulk gauge symmetry is broken down to the standard model gauge group with an extra U ( 1 ) X by orbifold boundary conditions and the extra U ( 1 ) X is further broken through the U ( 1 ) B – L breaking with bulk hyper multiplets. We obtain the corrections of Kaluza–Klein massive modes to the running of the gauge couplings and discuss their implication to the successful gauge coupling unification.