119111711
Analysis of an extended scalar sector with S3 symmetry
We investigate the scalar potential of a general S3-symmetric three-Higgs-doublet model. The outcome of our analysis does not depend on the fermionic sector of the model. We identify a decoupling limit for the scalar spectrum of this scenario. In view of the recent LHC Higgs data, we show our numerical results only in the decoupling limit. Unitarity and stability of the scalar potential demand that many new scalars must be lurking below 1 TeV. We provide numerical predictions for h→γγ and h→Zγ signal strengths, which can be used to falsify the theory.
119230166
Nondecoupling of charged scalars in Higgs decay to two photons and symmetries of the scalar potential
A large class of two- and three-Higgs-doublet models with discrete symmetries has been employed in the literature to address various aspects of flavor physics. We analyze how the precision measurement of the Higgs to diphoton signal strength would severely constrain these scenarios due to the nondecoupling behavior of the charged scalars, to the extent that in the presence of exact discrete symmetry, the number of additional noninert scalar doublets can be constrained no matter how heavy the nonstandard scalars are. We demonstrate that if the scalar potential is endowed with appropriate global continuous symmetries together with soft breaking parameters, decoupling can be achieved thanks to the unitarity constraints on the mass-square differences of the heavy scalars.
118444203
Scalar sector properties of two-Higgs-doublet models with a global U(1) symmetry
A bstractWe analyze the scalar sector properties of a general class of two-Higgs-doublet models which has a global U(1) symmetry in the quartic terms. We find constraints on the parameters of the potential from the considerations of unitarity of scattering amplitudes, the global stability of the potential and the ρ-parameter. We concentrate on the spectrum of the non-standard scalar masses in the decoupling limit which is preferred by the Higgs data at the LHC. We exhibit charged-Higgs induced contributions to the diphoton decay width of the 125 GeV Higgs boson and its correlation with the corresponding Zγ width.
106403057
Search for a stable alignment limit in two-Higgs-doublet models
We study the conditions required to make the two-Higgs-doublet-model (2HDM) scalar potential stable up to the Planck scale. The lightest CP-even scalar is assumed to have been found at the LHC and the alignment limit is imposed in view of the LHC Higgs data. We find that ensuring stability up to scales 1010GeV necessitates the introduction of a soft breaking parameter in the theory. Even then, some interesting correlations between the nonstandard masses and the soft breaking parameter need to be satisfied. Consequently, a 2HDM becomes completely determined by only two nonstandard parameters, namely, tanβ and a mass parameter, m0, with tanβ3. These observations make a 2HDM, in the stable alignment limit, more predictive than ever.
118725297
Double trace flows and holographic RG in dS/CFT correspondence
A bstractIf there is a dS/CFT correspondence, time evolution in the bulk should translate to RG flows in the dual euclidean field theory. Consequently, although the dual field is expected to be non-unitary, its RG flows will carry an imprint of the unitary time evolution in the bulk. In this note we examine the prediction of holographic RG in de Sitter space for the flow of double and triple trace couplings in any proposed dual. We show quite generally that the correct form of the field theory beta functions for the double trace couplings is obtained from holography, provided one identifies the scale of the field theory with (i|T|) where T is the ‘time’ in conformal coordinates. For dS4, we find that with an appropriate choice of operator normalization, it is possible to have real n-point correlation functions as well as beta functions with real coefficients. This choice leads to an RG flow with an IR fixed point at negative coupling unlike in a unitary theory where the IR fixed point is at positive coupling. The proposed correspondence of Sp(N) vector models with de Sitter Vasiliev gravity provides a specific example of such a phenomenon. For dSd+1 with even d, however, we find that no choice of operator normalization exists which ensures reality of coefficients of the beta-functions as well as absence of n-dependent phases for various n-point functions, as long as one assumes real coupling constants in the bulk Lagrangian.
123139058
Conformal freedom and Kasner and Belinskii models
In this paper we show, in the context of the quantum mechanical principle of uncertainty, that if conformal freedom has a quantum character then Kasner and Belinskii models have a status quantum-mechanically different from some models, i.e. Robertson - Walker, Bianchi type I (some forms) and Bianchi type III models.
121418091
Quantum fluctuations near a black-hole singularity
Abstract We present here an investigation of the problem of quantum fluctuations near a black-hole singularity. We show that quantum fluctuations do not vanish near the singularity leading to the conclusion that black-hole singularities are unlikely to exist.
119205437
Bi-local construction of Sp(2N)/dS higher spin correspondence
A bstractWe derive a collective field theory of the singlet sector of the Sp(2N) sigma model. Interestingly the Hamiltonian for the bilocal collective field is the same as that of the O(N) model. However, the large-N saddle points of the two models differ by a sign. This leads to a fluctuation Hamiltonian with a negative quadratic term and alternating signs in the nonlinear terms which correctly reproduces the correlation functions of the singlet sector. Assuming the validity of the connection between O(N) collective fields and higher spin fields in AdS, we argue that a natural interpretation of this theory is by a double analytic continuation, leading to the dS/CFT correspondence proposed by Anninos, Hartman and Strominger. The bi-local construction gives a map into the bulk of de Sitter space-time. Its geometric pseudospin-representation provides a framework for quantization and definition of the Hilbert space. We argue that this is consistent with finite N Grassmannian constraints, establishing the bi-local representation as a nonperturbative framework for quantization of Higher Spin Gravity in de Sitter space.
119230769
Performance and First Physics Results of the ALICE Muon Spectrometer
Abstract A precise measurement of the heavy-flavor production cross-sections in pp collisions is an essential baseline for the heavy-ion program. In addition it is a crucial test of pQCD models in the new energy regime at LHC. ALICE measures the muons from the decay of charmonium resonances and from the semileptonic decay of heavy-flavored hadrons in its forward ( − 4.0 η − 2.5 ) Muon Spectrometer. We discuss the status of the detector and present results of data taken in pp collisions at s = 7 TeV .