1312498
Algebra of Majorana doubling.
Motivated by the problem of identifying Majorana mode operators at junctions, we analyze a basic algebraic structure leading to a doubled spectrum. For general (nonlinear) interactions the emergent mode creation operator is highly nonlinear in the original effective mode operators, and therefore also in the underlying electron creation and destruction operators. This phenomenon could open up new possibilities for controlled dynamical manipulation of the modes. We briefly compare and contrast related issues in the Pfaffian quantum Hall state.
55734650
Critical Exponents for Supercooled Liquids
We compute critical exponents governing universal features of supercooled liquids through the effective theory of an overlap field. The correlation length diverges with the Ising exponent; the size of dynamically heterogeneous patches grows more rapidly; and the relaxation time obeys a generalized Vogel-Fulcher-Tammann relation.
17526644
GLSMs for non-Kähler geometries
A bstractWe identify a simple mechanism by which H-flux satisfying the modified Bianchi identity arises in garden-variety (0, 2) gauged linear sigma models. Taking suitable limits leads to effective gauged linear sigma models with Green-Schwarz anomaly cancellation. We test the quantum-consistency of a class of such effective theories by constructing an off-shell superconformal algebra, identifying unexpected topological constraints on the existence of this algebra and providing evidence that these models run to good CFTs in the deep IR when all of the constraints are satisfied.
54190218
The N=8$$ \mathcal{N}=8 $$ superconformal bootstrap in three dimensions
A bstractWe analyze the constraints imposed by unitarity and crossing symmetry on the four-point function of the stress-tensor multiplet of N=8$$ \mathcal{N}=8 $$ superconformal field theories in three dimensions. We first derive the superconformal blocks by analyzing the superconformal Ward identity. Our results imply that the OPE of the primary operator of the stress-tensor multiplet with itself must have parity symmetry. We then analyze the relations between the crossing equations, and we find that these equations are mostly redundant. We implement the independent crossing constraints numerically and find bounds on OPE coefficients and operator dimensions as a function of the stress-tensor central charge. To make contact with known N=8$$ \mathcal{N}=8 $$ superconformal field theories, we compute this central charge in a few particular cases using supersymmetric localization. For limiting values of the central charge, our numerical bounds are nearly saturated by the large N limit of ABJM theory and also by the free U(1) × U(1) ABJM theory.
126050167
Glassy slowdown and replica instantons
Supercooled liquids exhibit a dramatic dynamical slowdown as the temperature is lowered. This can be attributed to relaxation proceeding via large structural rearrangements, whose characteristic size increases as the temperature decreases. These cooperative rearrangements are well modeled by instantons in a replica effective field theory, with the size of the dominant instanton encoding the liquid’s cavity point-to-set correlation length. We show that, for a wide range of parameters, a novel class of replica-symmetry-breaking instantons dominates. We systematically construct these instantons and explore the subtle energetics governing their existence. Our methods extend naturally to the full parameter space of the replica effective theory, laying the groundwork for a complete analysis of point-to-set correlations in glassy systems.
119097109
Model independent analysis of the forward–backward asymmetry of top quark production at the Tevatron
Abstract Motivated by a possible anomaly in the forward–backward (FB) asymmetry of top quark ( A FB ) observed at the Tevatron, we perform a model independent analysis on q q ¯ → t t ¯ using an effective Lagrangian with dim-6 four-quark operators. We derive necessary conditions on new physics structures and the couplings that are consistent with the t t ¯ production cross section and A FB measured at the Tevatron, and discuss possible new physics scenarios that could generate such dim-6 operators.
119179020
Holomorphic supersymmetric Nambu--Jona-Lasinio model with application to dynamical electroweak symmetry breaking
Based on our idea of an alternative supersymmetrization of the Nambu-Jona-Lasinio model for dynamical symmetry breaking, we analyze the resulting new model with a holomorphic dimension-five operator in the superpotential. The approach provides a new direction for modeling dynamical symmetry breaking in a supersymmetric setting. In particular, we adopt the idea to formulate a model that gives rise to the minimal supersymmetric standard model as the low energy effective theory with both Higgs superfields as composites. A renormalization group analysis is performed to establish the phenomenological viability of the scenario, with admissible background scale that could go down to the TeV scale. We give the Higgs mass range predicted.
3289948
Flavour geometry and effective Yukawa couplings in the MSSM
We present a new geometric approach to the flavour decomposition of an arbitrary soft supersymmetry-breaking sector in the MSSM. Our approach is based on the geometry that results from the quark and lepton Yukawa couplings, and enables us to derive the necessary and sufficient conditions for a linearly-independent basis of matrices related to the completeness of the internal [SU(3)⊗U(1)]5 flavour space. In a second step, we calculate the effective Yukawa couplings that are enhanced at large values of tan β for general soft supersymmetry-breaking mass parameters. We highlight the contributions due to non-universal terms in the flavour decompositions of the sfermion mass matrices. We present numerical examples illustrating how such terms are induced by renormalization-group evolution starting from universal input boundary conditions, and demonstrate their importance for the flavour-violating effective Yukawa couplings of quarks.
126179603
Measurement of |V(ub) / V(cb)| (and |V(ub)|) in exclusive nonleptonic decays within the generalized factorization scheme
Within the generalized factorization scheme, we study extracting $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|$ by calculating the ratios $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}_{s}^{(*)\ensuremath{-}}({\ensuremath{\pi}}^{+},{\ensuremath{\rho}}^{+}))/\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}_{s}^{(*)\ensuremath{-}}{D}^{(*)+})$ including penguin effects. The ratios involving the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{+}$ mode have considerable penguin corrections $(\ensuremath{\sim}15%$ at the amplitude level), but those involving the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{*+}$ mode have relatively small penguin corrections. On the other hand, the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{+}$ mode has a smaller form-factor dependence. Therefore, these ratios complement each other in measuring ${V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}.$ The theoretical uncertainty from the hadronic form factors in our method is at the level of 20%, which is comparable to the model dependence uncertainty of about 20% in the measurement of $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|$ from the exclusive semileptonic B decays. Using the newest upper limit on $\stackrel{\ensuremath{\rightarrow}}{B}{D}_{s}\ensuremath{\pi}$ decay from CLEO, our method sets an upper limit $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|l0.13$ which is very close to the measured values from the semileptonic B decays.
118342811
LONG-TERM PHOTOMETRIC BEHAVIOR OF THE ECLIPSING BINARY GW CEPHEI
New CCD photometry over four successive years from 2005 is presented for the eclipsing binary GW Cep, together with reasonable explanations for the light and period variations. All historical light curves, obtained over a 30 yr interval, display striking light changes, and are best modeled by the simultaneous existence of a cool spot and a hot spot on the more massive cool component star. The facts that the system is magnetically active and that the hot spot has consistently existed on the inner hemisphere of the star indicate that the two spots are formed by (1) magnetic dynamo-related activity on the cool star and (2) mass transfer from the primary to the secondary component. Based on 38 light-curve timings from the Wilson-Devinney code and all other minimum epochs, a period study of GW Cep reveals that the orbital period has experienced a sinusoidal variation with a period and semi-amplitude of 32.6 yr and 0.009 days, respectively. In principle, these may be produced either by a light-travel-time effect due to a third body or by an active magnetic cycle of at least one component star. Because we failed to find any connection between luminosity variability and the period change, that change most likely arises from the existence of an unseen third companion star with a minimum mass of 0.22 M ☉ gravitationally bound to the eclipsing pair.