Showing papers by "Mikhail Shaposhnikov published in 2015"
TL;DR: The SHiP (Search for Hidden Particles) experiment at CERN as discussed by the authors was designed to search for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments.
Abstract: This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (Search for Hidden Particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, $\tau\to 3\mu$ and to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the Standard Model and describe interactions between new particles and four different portals - scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the Standard Model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation
592 citations
Posted Content•
TL;DR: A new general purpose fixed target facility is proposed at the CERN SPS accelerator which is aimed at exploring the domain of hidden particles and making measurements with tau neutrinos as discussed by the authors.
Abstract: A new general purpose fixed target facility is proposed at the CERN SPS accelerator which is aimed at exploring the domain of hidden particles and make measurements with tau neutrinos. Hidden particles are predicted by a large number of models beyond the Standard Model. The high intensity of the SPS 400~GeV beam allows probing a wide variety of models containing light long-lived exotic particles with masses below ${\cal O}$(10)~GeV/c$^2$, including very weakly interacting low-energy SUSY states. The experimental programme of the proposed facility is capable of being extended in the future, e.g. to include direct searches for Dark Matter and Lepton Flavour Violation.
360 citations
TL;DR: In this article, it was shown that the successful Higgs inflation scenario can also take place if the SM vacuum is not absolutely stable, based on two effects that were overlooked previously: effective renormalization of the SM couplings at the energy scale M-P/xi and symmetry restoration after inflation due to high temperature effects.
Abstract: The measurements of the Higgs mass and top Yukawa coupling indicate that we live in a very special universe, at the edge of the absolute stability of the electroweak vacuum. If fully stable, the Standard Model (SM) can be extended all the way up to the inflationary scale and the Higgs field, nonminimally coupled to gravity with strength xi, can be responsible for inflation. We show that the successful Higgs inflation scenario can also take place if the SM vacuum is not absolutely stable. This conclusion is based on two effects that were overlooked previously. The first one is associated with the effective renormalization of the SM couplings at the energy scale M-P/xi, where M-P is the Planck scale. The second one is a symmetry restoration after inflation due to high temperature effects that leads to the (temporary) disappearance of the vacuum at Planck values of the Higgs field.
228 citations
TL;DR: In this article, the authors present a Web of Science Record created on 2015-05-29, modified on 2016-08-09 and used for the purpose of Web-of-Science Record.
Abstract: Reference EPFL-ARTICLE-208533doi:10.1007/Jhep02(2015)028View record in Web of Science Record created on 2015-05-29, modified on 2016-08-09
20 citations
TL;DR: I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe.
Abstract: I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production.
17 citations
01 Jan 2015
TL;DR: The effects of overexpression of DNA repair genes implicated in DNA repair on lifespan and resistance to stress factors in Drosophila melanogaster are demonstrated for the first time.
Abstract: DNA repair declines with age and correlates with longevity in many animal species. In this study, we investigated the effects of GAL4-induced overexpression of genes implicated in DNA repair on lifespan and resistance to stress factors in Drosophila melanogaster. Stress factors included hyperthermia, oxidative stress, and starvation. Overexpression was either constitutive or conditional and either ubiquitous or tissue-specific (nervous system). Overexpressed genes included those involved in recognition of DNA damage (homologs of HUS1, CHK2), nucleotide and base excision repair (homologs of XPF, XPC and AP-endonuclease-1), and repair of double-stranded DNA breaks (homologs of BRCA2, XRCC3, KU80 and WRNexo). The overexpression of different DNA repair genes led to both positive and negative effects on lifespan and stress resistance. Effects were dependent on GAL4 driver, stage of induction, sex, and role of the gene in the DNA repair process. While the constitutive/neuron-specific and conditional/ubiquitous overexpression of DNA repair genes negatively impacted lifespan and stress resistance, the constitutive/ubiquitous and conditional/ neuron-specific overexpression of Hus1, mnk, mei-9, mus210, and WRNexo had beneficial effects. This study demonstrates for the first time the effects of overexpression of these DNA repair genes on both lifespan and stress resistance in D. melanogaster.
14 citations
TL;DR: In this article, a new type of topological vortex solution was found in the U(1)(Z) xU(1) A Chern-Simons gauge theory in the presence of a U( 1)(A) magnetic field background.
Abstract: We find a new type of topological vortex solution in the U(1)(Z) xU(1)(A) Chern-Simons gauge theory in the presence of a U(1)(A) magnetic field background. In this theory U(1)(Z) is broken spontaneously by the U(1)(A) magnetic field. These vortices exhibit long-range interactions as they are charged under the unbroken U(1)(A). They deplete the U(1)(A) magnetic field near their core and also break both charge conjugation and parity symmetries. Understanding the nature of these vortices sheds light on the ground state structure of the superconductivity studied in [1]. We also study the Berezinsky-Kosterlitz-Thouless phase transition in this class of theories and point out that superconductivity can be achieved at high temperatures by increasing the U(1)(A) magnetic field.
5 citations
TL;DR: In this article, the existence of the vortex is envisaged by analytical means, and a numerical solution is obtained by integrating the equations of motion by integrating a new topological vortex solution in U (1) x U(1) theory.
Abstract: We report on a new topological vortex solution in U(1) x U(1) Maxwell-Chern-Simons theory. The existence of the vortex is envisaged by analytical means, and a numerical solution is obtained by integrating the equations of motion. These vortices have a long-range force because one of the U(1)'s remains unbroken in the infrared, which is guarded by the Coleman-Hill theorem. The sum of the winding numbers of an ensemble of vortices has to vanish; otherwise the system would have a logarithmically divergent energy. In turn, these vortices exhibit classical confinement. We investigate the rich parameter space of the solutions, and show that one recovers the Abrikosov-Nielsen-Olesen, U(1) Maxwell-Chern-Simons, U(1) pure Chern-Simons, and global vortices as various limiting cases. Unlike these limiting cases, the higher winding solutions of our vortices carry noninteger charges under the broken U(1). This is the first vortex solution exhibiting such behavior.
4 citations
3 citations