121621613
Fractionally charged lepton and low-mass magnetic monopole
We study an SO(14) model to obtain a low-mass magnetic monopole and fractionally charged leptons. The mass of the magnetic monopole is roughly-equal2 x 10/sup 9/ GeV.
56138229
Gauge CP symmetry, wormhole effects, and strong CP problem
The recent observation of four dimensional CP as a discrete gauge symmetry in 8k + 1, 8k + 2 and 8k + 3 Minkowski dimensions calls for a serious reconsid­ eration of various solutions of the strong CP problem. In these possible higher dimensions, the relevant one is a ten dimensional string theory in which a possi­ bility of light fermions exists. We point out that the model independent axion in the heterotic string theory solves the strong CP problem. We also point out that the wormhole effects to low energy global and discrete symmetries are negligible. .. " JIf',!\f':-,',f,' ,. aJ , I <\ " ; \ ,k fL .::LJ.i2" ('If"T 11 . J' ., __ ".1: 1992 11!llllnrB1i1111111 -SAlUT? -·9/ --..5~ o 11bO 0011852 5 .................. • The recent observation of four dimensional CP as a discrete gauge symmetry in 8k +1, 8k +2 and 8k +3 Minkowski dimensions [1] calls for a new understand­ ing on the weak CP violation and the strong CP invariance. Among the possible higher dimensions, the relevant one is 10 because there exists a phenomenologi­ cally viable heterotic string theory [2]. The other extra dimensions not utilized by nature are only of academic interest. In the heterotic string theory, it has been known that the four dimensional CP must be a gauge symmetry since the theory does not have any discrete symmetry except Es +-+ E~ [3]. The discrete symmetry Es +-+ E~ cannot contain the four dimensional CP of light fermions and anti-fermions since they are singlets of E~. In string theories, therefore, the required weak CP violation must arise through spontaneous breaking [4]. The Kobayashi-Maskawa weak CP phase which looks like a hard CP violation at low energy may in fact have descended down from string scale physics through spon­ taneous breaking mechanism [5]. Inflation after the spontaneous CP violation might have removed the dangerous domain walls from our observable universe. The 'calculability' solutions of the Nelson-Barr type [6] to the strong CP problem have a rationale (8QCD = 0) in higher dimensions due to CP as a discrete gauge symmetry of Lagrangian. However, there are two questions to be cleared regarding the strong CP prob­ lem. Firstly, should we consider extra dimensions? Second, what is the effect of gravity on the four dimensional low energy symmetries? In this Letter, we consider both of these questions from Planck scale physics. Regarding the first question, an extension of spatial dimensions should not be in contradiction with low energy physics. Phenomenologically, there is no reason to extend the spatial dimensions. However, one may try to include more spatial dimensions to solve theoretical problems of the standard model. So in consideration of dis'crete and global symmetries in higher dimensions, at present the ten dimensional heterotic string is the only one to be considered. Thus, let us consider the (} parameter in the heterotic string theory in ten dimension. The heterotic string has a model-independent axion aMI [7] whose decay constant is
119316975
GMSB at a stable vacuum and MSSM without exotics from heterotic string
Abstract We show that it is possible to introduce the confining hidden sector gauge group SU ( 5 ) ′ with the chiral matter 10 0 ′ plus 5 ¯ 0 ′ , which are neutral under the standard model gauge group, toward a gauge mediated supersymmetry breaking (GMSB) in a Z 12 − I orbifold compactification of E 8 × E 8 ′ heterotic string. Three families of MSSM result without exotics. We also find a desirable matter parity P (or R-parity) assignment. We note that this model contains the spectrum of the Lee–Weinberg model which has a nice solution of the μ problem.
14574575
Effective Gauss-Bonnet interaction in Randall-Sundrum compactification
The effective gravitational interaction below the Planck scale in the Randall-Sundrum world is shown to be the Gauss-Bonnet term. In this theory we find that there exists another static solution with a positive bulk cosmological constant. Also, there exist solutions for a positive visible sector cosmological constant, which is needed for a later Friedmann-Robertson-Walker universe.
13291931
Hidden sector gaugino condensation and the model independent axion
Abstract In the effective field theory framework, we consider the effect of supersymmetry breaking via gaugino condensation and supergravity in the hidden sector gauge group on the hidden sector vacuum angle θ h . The θ h parameter dependence of the potential yields phenomenologically acceptable invisible axion solutions if the U (1) R symmetry is broken down to a discrete subgroup Z N with N ≥3 ( N =4 is marginal). Anomalous U(1) superstring models are good candidates for this invisible axion resolution of the strong CP puzzle.
18138135
Neutrino masses from discrete gauge symmetries
Abstract We investigate a model with an extra Z 2 gauge symmetry in the Standard Model. The symmetry gives a structure to the mass matrix for the neutrinos. With two extra Higgs singlets and two extra singlet right-handed neutrinos we can build a model that fits the requirements of the MSW solution of the Solar neutrino problem. With a third singlet right-handed neutrino it is also possible to have a 10 eV neutrino.
16726847
Testing neutrino masses in the R-parity violating minimal supersymmetric standard model with LHC results
Within the R–parity violating minimal supersymmetric standard model (MSSM), we use a hierarchical ansatz for the lepton–number violating trilinear Yukawa couplings by relating them to the corresponding Higgs–Yukawa couplings. This ansatz reduces the number of free parameters in the lepton–number violating sector from 36 to 6. Baryon–number violating terms are forbidden by imposing the discrete gauge symmetry Baryon Triality. We fit the lepton–number violating parameters to the most recent neutrino oscillation data, including the mixing angle θ13 found by Daya Bay. We find that we obtain phenomenologically viable neutrino masses and mixings only in the case of normal ordered neutrino masses and that the lepton–number violating sector is unambiguously determined by neutrino oscillation data. We discuss the resulting collider signals for the case of a neutralino as well as a scalar tau lightest supersymmetric particle. We use the ATLAS searches for multi–jet events and large transverse missing momentum in the 0, 1 and 2 lepton channel with 7 TeV center–of–mass energy in order to derive exclusion limits on the parameter space of this R–parity violating supersymmetric model.
118704767
First LHC Constraints on Neutralinos
Abstract The ATLAS and CMS Collaborations have recently reported tantalizing hints of the existence of a 125 GeV Higgs-like particle, whose couplings appear to match well the Standard Model (SM) expectations. In this work, we study implications of this observation for the neutralino sector of supersymmetric models, assuming that the Higgs signal gets confirmed. In general, the Higgs decay into neutralinos can be one of its dominant decay channels. Since a large invisible Higgs decay branching ratio would be in conflict with the data, this possibility is now constrained. In particular, we find that most of the region μ 170 GeV , M 1 70 GeV at tan β ∼ 10 and μ 120 GeV , M 1 70 GeV at tan β ∼ 40 is disfavored.
1556990
Optimizing interferometer experiments for CMB B mode measurement
The sensitivity of interferometers with linear polarizers to the CMB E and B mode are variant under the rotation of the polarizer frame, while interferometer with circular polarizers are equally sensitive to E and B mode. We present analytically and numerically that the diagonal elements of window functions for CMB E/B power spectra are maximized in interferometric measurement of linear polarization, when the polarizer frame is in certain rotation from the associated baseline. We also present the simulated observation to show that the 1σ errors on E/B mode power spectrum estimation are variant under the polarizer frame rotation in the case of linear polarizers, while they are invariant in the case of circular polarizers. Simulation of the configuration similar to the DASI shows that minimum 1σ error on B mode in interferometer measurement with linear polarizers is 26 per cent of that in interferometric measurement with circular polarizers. The simulation also shows that the E/B mixing in interferometer measurement with linear polarizers can be as low as 23 per cent of that in interferometric measurement with circular polarizers. It is not always possible to physically align the polarizer frame with all the associated baselines in the case of an interferometer array (N>2). There exist certain linear combinations of visibilities, which are equivalent to visibilities of the optimal polarizer frame rotation. We present the linear combinations, which enables B mode optimization for an interferometer array (N>2).
118343398
Probing Minimal Flavor Violation with Long-Lived Stops and Light Gravitinos at Hadron Colliders
In the framework of minimal flavor violation (MFV), we discuss the decay properties of a supersymmetric scalar top (stop) in the presence of a light gravitino. Given a small mass difference between the lighter stop and lightest neutralino and an otherwise sufficiently decoupled spectrum, the stop may be long-lived and thus can provide support to MFV at hadron colliders. For a bino-like lightest neutralino, we apply bounds from searches in the gamma gamma plus missing transverse energy channel (ATLAS with 1 fb^-1 and D0 with 6.3 fb^-1) and give a 5 fb^-1 projection for the ATLAS search.
119291744
Neutrino masses and mixings in the baryon triality constrained minimal supersymmetric standard model
We discuss how the experimental neutrino oscillation data can be realized in the framework of the baryon triality ($B_3$) constrained supersymmetric Standard Model (cSSM). We show how to obtain phenomenologically viable solutions, which are compatible with the recent WMAP observations. We present results for the hierarchical, inverted and degenerate cases which illustrate the possible size and structure of the lepton number violating couplings. We work with a new, as yet unpublished version of SOFTSUSY, where we implemented full one--loop neutrino masses. Finally, we shortly discuss some phenomenological implications at the LHC.