Mikhail Chapochnikov

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Higgs inflation can occur if the Standard Model (SM) is a self-consistent effective field theory up to inflationary scale. This leads to an upper bound on the top Yukawa coupling, y(t)(phys) < y(t)(crit) and thus on the mass of the top quark m(t). If m(t) ...

The Search for Hidden Particles (SHiP) experiment proposal at CERN demands a dedicated dipole magnet for its scattering and neutrino detector. This requires a very large volume to be uniformly magnetized at B > 1.2 T, with constraints regarding the inner i ...

The diversity of structures in the Universe (from the smallest galaxies to the largest superclusters) has formed under the pull of gravity from the tiny primordial perturbations that we see imprinted in the cosmic microwave background. A quantitative descr ...

We construct a class of theories which are scale-invariant on quantum level in all orders of perturbation theory. In a subclass of these models scale invariance is spontaneously broken, leading to the existence of a massless dilaton. The applications of th ...

An intriguing feature of the Standard Model is that the representations of the unbroken gauge symmetries are vector-like whereas those of the spontaneously broken gauge symmetries are chiral. Here we provide a toy model which shows that a natural explanati ...

Long-range muons produced in proton–proton collisions at the ATLAS interaction point constitute the primary background for neutrino interaction searches at the SND@LHC experiment. This work presents a comprehensive characterization of the muon flux throughout LHC Run-3, benchmarking Monte Carlo simulations against experimental measurements. Measured and simulated muon rates agree within 10–15% across all Run-3 configurations. Following the substantial background increase in 2024 as a result of a beam optics

We explore the range of parameters for dark-matter sterile neutrinos in an extension of the Minimal Standard Model by three singlet fermions with masses below the electroweak scale (the νMSM). This simple model can explain a wide range of phenomena, includ ...

Standard Model fails to explain neutrino oscillations, dark matter, and baryon asymmetry of the Universe. All these problems can be solved with three sterile neutrinos added to SM. Quite remarkably, if sterile neutrino masses are well below the electroweak ...

We propose a model for combining the Standard Model (SM) with gravity. It relies on a nonminimal coupling of the Higgs field to the Ricci scalar and on the Palatini formulation of gravity. Without introducing any new degrees of freedom in addition to those ...

The effective potential of the scalar field in the SU(5) model has extrema with symmetry:SU(5), SU(4)×U(1), SU(3)×SU(2)×U(1), SU(3)×[U(1)]2, [SU(2)]2×[U(1)]2. In our recent paper it was shown that the SU(4)×U(1) phase as well as SU(3)×SU(2)×U(1) phase were stable at the nonzero temperature in a vast region of parameters. In the present paper it is found that the [SU(2)]2×[U(1)]2 symmetric vacuum is unstable and the SU(3)×[U(1)]2 symmetric vacuum can be metastable in the certain interval of the temperature.

To confront the numerical results of Gamma(diff)with the analytical results from section 2.3, we originally considered the theoretical prediction for the diffusion rate given by eq. (2.17), which we re-wrote in eq. (4.25). ...

Quantum field theories with exact but spontaneously broken conformal invariance have an intriguing feature: their vacuum energy (cosmological constant) is equal to zero. Up to now, the only known ultraviolet complete theories where conformal symmetry can b ...

We consider a minimal scale-invariant extension of the standard model of particle physics combined with unimodular gravity formulated in [M. Shaposhnikov and D. Zenhausern, Phys. Lett. B 671, 187 (2009).]. This theory is able to describe not only an inflat ...

Right-handed neutrinos offer an elegant solution to two well-established phenomena beyond the Standard Model (SM)-masses and oscillations of neutrinos, as well as the baryon asymmetry of the Universe. It is also a minimalistic solution, since it requires o ...

How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysical cosmology. EDGE (Piro et al., 2007) will trace the cosmic history of the baryons from the early generations of massive ...

The Standard Model accompanied with two right-handed neutrinos with masses below the weak scale can explain the observed baryon asymmetry of the Universe. Moreover, this model is at least partially testable in the forthcoming experiments such as NA62, SHiP ...

After the Higgs boson has been discovered, the Standard Model of particle physics became a confirmed theory, potentially valid up to the Planck scale and allowing to trace the evolution of the Universe from inflationary stage till the present days. We disc ...

We consider spherically symmetric higher-dimensional solutions of Einstein's equations with a bulk cosmological constant and n transverse dimensions. In contrast to the case of one or two extra dimensions we find no solutions that localize gravity when n ≥ 3, for strictly local topological defects. We discuss global topological defects that lead to the localization of gravity and estimate the corrections to Newton's law. We show that the introduction of a bulk 'hedgehog' magnetic field leads to a regular ge

We discuss here the following questions related to magnetic fields in the early universe: 1. Observational constraints on primordial magnetic fields. 2. Different ideas put forward for explanation of large scale fields which can seed the galactic magnetic ...

Mikhail Chapochnikov

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Higgs inflation at the critical point

The magnet of the scattering and neutrino detector for the SHiP experiment at CERN

A new framework for numerical simulations of structure formation

Quantum scale invariance, cosmological constant and hierarchy problem

Chiral Asymmetry from a 5D Higgs Mechanism

Study of the Run-3 muon flux at the SND@LHC experiment

Opening a new window for warm dark matter

Search for GeV-Scale Sterile Neutrinos Responsible for Active Neutrino Oscillations and Baryon Asymmetry of the Universe

Standard model meets gravity: Electroweak symmetry breaking and inflation

PHASE PORTRAIT OF SU(5) MODEL. 2. INTERMEDIATE PHASES SU(3) X U(1)2 AND SU(2)2 X U(1)**2

Anomalous non-conservation of fermion/chiral number in Abelian gauge theories at finite temperature (vol 4, 26, 2018)

Spontaneous conformal symmetry breaking in fishnet CFT

Higgs-dilaton cosmology: From the early to the late Universe

Reconciling resonant leptogenesis and baryogenesis via neutrino oscillations

EDGE: Explorer of diffuse emission and gamma-ray burst explosions

Parameter space of baryogenesis in the nu MSM

Inflation, LHC and the Higgs boson

Living inside a hedgehog: Higher-dimensional solutions that localize gravity

Baryogenesis

Primordial magnetic fields