814 research outputs found
Higgs inflation and suppression of axion isocurvature perturbation
We point out that cosmological constraint from the axion isocurvature perturbation is relaxed if the Higgs field obtains a large field value during inflation in the DFSZ axion model. This scenario is consistent with the Higgs inflation model, in which two Higgs doublets have non-minimal couplings and play a role of inflaton
Cosmic-ray neutrinos from the decay of long-lived particle and the recent IceCube result
Motivated by the recent IceCube result, we study high energy cosmic-ray neutrino flux from the decay of a long-lived particle. Because neutrinos are so transparent, high energy neutrinos produced in the past may also contribute to the present neutrino flux. We point out that the PeV neutrino events observed by IceCube may originate in the decay of a particle much heavier than PeV if its lifetime is shorter than the present cosmic time. It is shown that the mass of the particle responsible for the IceCube event can be as large as <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mo>∼</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>10</mn></mrow></msup><mtext> GeV</mtext></math> . We also discuss several possibilities to acquire information about the lifetime of the long-lived particle
Cosmological implications of high-energy neutrino emission from the decay of long-lived particle
We study cosmological scenarios in which high-energy neutrinos are emitted from the decay of long-lived massive particles at the cosmic time later than a redshift of ∼ 10 6 . The high-energy neutrino events recently observed by the IceCube experiment suggest a new source of high-energy cosmic-ray neutrinos; decay of a heavy particle can be one of the possibilities. We calculate the spectrum of the high-energy neutrinos emitted from the decay of long-lived particles, taking account of the neutrino scattering processes with background neutrinos. Then, we derive bounds on the scenario using the observation of high-energy cosmic-ray neutrino flux. We also study constraints from the spectral distortions of the cosmic microwave background and the big-bang nucleosynthesis. In addition, we show that the PeV neutrinos observed by the IceCube experiment can originate from the decay of a massive particle with its mass as large as O (10 10 GeV)
Heavy WIMP through Higgs portal at the LHC
The LHC constraints on Higgs-portal WIMPs are studied. Scalar, vector and anti-symmetric tensor fields are considered. They are assumed to be heavier than a half of the Higgs boson mass. We investigate 8 TeV LHC results on signatures of the vector boson fusion, mono-jet and associated production of the Z boson, which proceed via virtual exchange of the Higgs boson. We show that the vector boson fusion channel gives the most stringent constraints on Higgs-portal interactions for all the WIMP models investigated here. The upper limits on vector and tensor Higgs-portal couplings can be 0.43 and 0.16 for the WIMP mass of 65 GeV, respectively. However, they are rapidly weakened for heavier WIMP masses, allowing O(1) couplings for masses heavier than ∼100 GeV . Constraints for scalar WIMPs are very weak. Prospects of the 14 TeV LHC are also discussed. We show that the constraints on the tensor and vector couplings would be improved by a factor of ∼1.5–2 , depending on the search channels. It would be still challenging to constrain scalar WIMPs
Exact results for boundaries and domain walls in 2d supersymmetric theories
We apply supersymmetric localization to N = 2 2 gauged linear sigma models on a hemisphere, with boundary conditions, i.e., D-branes, preserving B-type supersymmetries. We explain how to compute the hemisphere partition function for each object in the derived category of equivariant coherent sheaves, and argue that it depends only on its K theory class. The hemisphere partition function computes exactly the central charge of the D-brane, completing the well-known formula obtained by an anomaly inflow argument. We also formulate supersymmetric domain walls as D-branes in the product of two theories. In particular 4d line operators bound to a surface operator, corresponding via the AGT relation to certain defects in Toda CFT’s, are constructed as domain walls. Moreover we exhibit domain walls that realize the sl (2) affine Hecke algebra
Lepton-flavor violations in high-scale SUSY with right-handed neutrinos
Motivated by the recent discovery of the Higgs boson at <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>m</mi></mrow><mrow><mi>h</mi></mrow></msub><mo>≃</mo><mn>126</mn><mtext> GeV</mtext></math> and also by the non-observation of superparticles at the LHC, high-scale SUSY, where the superparticles are as heavy as <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mi>O</mi><mo stretchy="false">(</mo><mn>10</mn><mo stretchy="false">)</mo><mtext> TeV</mtext></math> , has been recently proposed. We study lepton-flavor violations (LFVs) in the high-scale SUSY with right-handed neutrinos. Even if the slepton masses are of <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mi>O</mi><mo stretchy="false">(</mo><mn>10</mn><mo stretchy="false">)</mo><mtext> TeV</mtext></math> , the renormalization group (RG) effects on the slepton mass-squared matrix may induce large enough LFVs which are within the reach of future LFV experiments. We also discuss the implication of the right-handed neutrinos on the electroweak symmetry breaking in such a model, and show that the parameter region with the successful electroweak symmetry breaking is enlarged by the RG effects due to the right-handed neutrinos
ODE/IM correspondence and modified affine Toda field equations
We study the two-dimensional affine Toda field equations for affine Lie algebra <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mover accent="true"><mrow><mi mathvariant="fraktur">g</mi></mrow><mrow><mo stretchy="false">ˆ</mo></mrow></mover></math> modified by a conformal transformation and the associated linear equations. In the conformal limit, the associated linear problem reduces to a (pseudo-)differential equation. For classical affine Lie algebra <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mover accent="true"><mrow><mi mathvariant="fraktur">g</mi></mrow><mrow><mo stretchy="false">ˆ</mo></mrow></mover></math> , we obtain a (pseudo-)differential equation corresponding to the Bethe equations for the Langlands dual of the Lie algebra <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="fraktur">g</mi></math> , which were found by Dorey et al. in study of the ODE/IM correspondence
The Higgs boson mass and SUSY spectra in 10D SYM theory with magnetized extra dimensions
We study the Higgs boson mass and the spectrum of supersymmetric (SUSY) particles in the well-motivated particle physics model derived from a ten-dimensional supersymmetric Yang–Mills theory compactified on three factorizable tori with magnetic fluxes. This model was proposed in a previous work, where the flavor structures of the standard model including the realistic Yukawa hierarchies are obtained from non-hierarchical input parameters on the magnetized background. Assuming moduli- and anomaly-mediated contributions dominate the soft SUSY breaking terms, we study the precise SUSY spectra and analyze the Higgs boson mass in this mode, which are compared with the latest experimental data
The Higgs particle and higher-dimensional theories
In spite of the great success of LHC experiments, we do not know whether the discovered standard model-like Higgs particle is really what the standard model predicts, or a particle that some new physics has in its low-energy effective theory. Also, the long-standing problems concerning the property of the Higgs and its interactions are still there, and we still do not have any conclusive argument on the origin of the Higgs itself. In this article we focus on higher-dimensional theories as new physics. First we give a brief review of their representative scenarios and closely related 4D scenarios. Among them, we mainly discuss two interesting possibilities of the origin of the Higgs: the Higgs as a gauge boson and the Higgs as a (pseudo) NambuGoldstone boson. Next, we argue that theories of new physics are divided into two categories, i.e., theories with normal Higgs interactions and those with anomalous Higgs interactions. Interestingly, both the candidates for the origin of the Higgs mentioned above predict characteristic anomalous Higgs interactions, such as the deviation of the Yukawa couplings from the standard model predictions. Such deviations can hopefully be investigated by precision tests of Higgs interactions at the planned ILC experiment. Also discussed is the main decay mode of the Higgs, . Again, theories belonging to different categories are known to predict remarkably different new physics contributions to this important process
Weighing the light gravitino mass with weak lensing surveys
We explore the discovery potential of light gravitino mass m 3/2 by combining future cosmology surveys and collider experiments. The former probe the imprint of light gravitinos in the cosmic matter density field, whereas the latter search signatures of a supersymmetry breaking mechanism. Free-streaming of light gravitinos suppresses the density fluctuations at galactic and sub-galactic length scales, where weak gravitational lensing can be used as a powerful probe. We perform numerical simulations of structure formation to quantify the effect. We then run realistic ray-tracing simulations of gravitational lensing to measure the cosmic shear in models with light gravitino. We forecast the possible reach of future wide-field surveys by Fisher analysis; the light gravitino mass can be determined with an accuracy of m 3/2 = 4 ± 1 eV by a combination of the Hyper Suprime Cam survey and cosmic microwave background anisotropy data obtained by Planck satellite. The corresponding accuracy to be obtained by the future Large Synoptic Survey Telescope is δm 3/2 = 0 . 6 eV. Data from experiments at Large Hadron Collider at 14 TeV will provide constraint at m 3/2 ≃ 5 eV in the minimal framework of gauge-mediated supersymmetry breaking (GMSB) model. We conclude that a large class of the GMSB model can be tested by combining the cosmological observations and the collider experiments
- …