Moscow Institute of Physics and Technology

About: Moscow Institute of Physics and Technology is a education organization based out in Dolgoprudnyy, Russia. It is known for research contribution in the topics: Laser & Large Hadron Collider. The organization has 8594 authors who have published 16968 publications receiving 246551 citations. The organization is also known as: MIPT & Moscow Institute of Physics and Technology (State University).

Observation of neutronless fusion reactions in picosecond laser plasmas

Abstract: The yield of $\ensuremath{\alpha}$ particles in neutronless fusion reactions $^{11}\mathrm{B}+p$ in plasmas produced by picosecond laser pulses with the peak intensity of $2\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$ has been observed. Experiments were carried out on the ``Neodymium'' laser facility at the pulse energy of $10--12\phantom{\rule{0.3em}{0ex}}\mathrm{J}$ and pulse duration of $1.5\phantom{\rule{0.3em}{0ex}}\mathrm{ps}$. The composite targets $^{11}\mathrm{B}+{(\mathrm{C}{\mathrm{H}}_{2})}_{n}$ were used. The yield of ${10}^{3}$ $\ensuremath{\alpha}$ particles per pulse has been observed. The energy spectrum of $\ensuremath{\alpha}$ particles contains two maxima: at $3--4\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ and at $6--10\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$. The first of these peaks corresponds to the secondary ${\ensuremath{\alpha}}_{12}$ particles at the decay of the intermediate first excited state of $^{8}\mathrm{Be}$, whereas the second peak demonstrates generation of ${\ensuremath{\alpha}}_{1}$ particles in the reaction $^{11}\mathrm{B}+p$ with the production of this excited state. Simultaneous measurements of neutrons result in zero yield, which proves the observation of neutronless fusion reactions in our experiments.

Phenomenology of GeV-scale heavy neutral leptons

Abstract: We review and revise phenomenology of the GeV-scale heavy neutral leptons (HNLs). We extend the previous analyses by including more channels of HNLs production and decay and provide with more refined treatment, including QCD corrections for the HNLs of masses $$ \mathcal{O} $$ (1) GeV. We summarize the relevance of individual production and decay channels for different masses, resolving a few discrepancies in the literature. Our final results are directly suitable for sensitivity studies of particle physics experiments (ranging from proton beam-dump to the LHC) aiming at searches for heavy neutral leptons.

Waterlike thermodynamic anomalies in a repulsive-shoulder potential system.

Abstract: We report a computer-simulation study of the equilibrium phase diagram of a three-dimensional system of particles with a repulsive-shoulder potential. The phase diagram was obtained using free-energy calculations. At low temperatures, we observe a number of distinct crystal phases. We show that at certain values of the potential parameters the system exhibits the waterlike thermodynamic anomalies: a density anomaly and a diffusion anomaly. The anomalies disappear with increasing the repulsive step width: more precisely, their locations move to the region where the crystalline phase is stable.

Long-Lived Particles at the Energy Frontier: The MATHUSLA Physics Case

Abstract: We examine the theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of Standard Model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). In most cases the LLP lifetime can be treated as a free parameter from the $\mu$m scale up to the Big Bang Nucleosynthesis limit of $\sim 10^7$m. Neutral LLPs with lifetimes above $\sim$ 100m are particularly difficult to probe, as the sensitivity of the LHC main detectors is limited by challenging backgrounds, triggers, and small acceptances. MATHUSLA is a proposal for a minimally instrumented, large-volume surface detector near ATLAS or CMS. It would search for neutral LLPs produced in HL-LHC collisions by reconstructing displaced vertices (DVs) in a low-background environment, extending the sensitivity of the main detectors by orders of magnitude in the long-lifetime regime. In this white paper we study the LLP physics opportunities afforded by a MATHUSLA-like detector at the HL-LHC. We develop a model-independent approach to describe the sensitivity of MATHUSLA to BSM LLP signals, and compare it to DV and missing energy searches at ATLAS or CMS. We then explore the BSM motivations for LLPs in considerable detail, presenting a large number of new sensitivity studies. While our discussion is especially oriented towards the long-lifetime regime at MATHUSLA, this survey underlines the importance of a varied LLP search program at the LHC in general. By synthesizing these results into a general discussion of the top-down and bottom-up motivations for LLP searches, it is our aim to demonstrate the exceptional strength and breadth of the physics case for the construction of the MATHUSLA detector.