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Mikhail Chapochnikov

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Related publications (139)

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The Higgs boson and cosmology

Mikhail Chapochnikov

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 rad ...

Royal Soc2015

Gravity, scale invariance and the hierarchy problem

Mikhail Chapochnikov, Andrey Shkerin

Combining the quantum scale invariance with the absence of new degrees of freedom above the electroweak scale leads to stability of the latter against perturbative quantum corrections. Nevertheless, the hierarchy between the weak and the Planck scales rema ...

Springer Nature2018

Observational manifestations of anomaly inflow

Mikhail Chapochnikov, Alexey Boyarsky, Oleg Ruchayskiy

In theories with chiral couplings, one of the important consistency requirements is that of the cancellation of a gauge anomaly. In particular, this is one of the conditions imposed on the hypercharges in the standard model. However, anomaly cancellation c ...

American Physical Society2005

Neutrino physics within and beyond the three flavour oscillation

Mikhail Chapochnikov

I will discuss several possible choices for the mass scale M of the Majorana leptons, complementing the Standard Model to describe neutrino masses and oscillations. Depending on M, they can or cannot accommodate eV neutrino anomalies, lead to baryogenesis, ...

Iop Publishing Ltd2013

Gauge coupling unification without leptoquarks

Mikhail Chapochnikov, Georgios Karananas

We propose an interpretation of the gauge coupling unification scale which is not related to any new particle threshold. We revisit Grand Unified Theories and show that it is possible to completely eliminate the scalar as well as vector leptoquarks from th ...

2017

Higgs-Dilaton cosmology: Universality versus criticality

Mikhail Chapochnikov, Javier Rubio

The Higgs-Dilaton model is able to produce an early inflationary expansion followed by a dark energy dominated era responsible for the late time acceleration of the Universe. At tree level, the model predicts a small tensor-to-scalar ratio (0.0021

American Physical Society2014

Searching for dark matter sterile neutrino in laboratory

Mikhail Chapochnikov

If the dark matter of the Universe is made of sterile neutrinos with mass in the keV region, it can be searched for with the help of x-ray satellites. We discuss the prospects of laboratory experiments that can be competitive and complementary to space mis ...

American Physical Society2007

Scale-invariant alternatives to general relativity. II. Dilaton properties

Mikhail Chapochnikov, Georgios Karananas

In the present paper, we revisit gravitational theories which are invariant under TDiffs-transverse (volume-preserving) diffeomorphisms and global scale transformations. It is known that these theories can be rewritten in an equivalent diffeomorphism-invar ...

American Physical Society2016

Scale and Weyl invariance in Einstein-Cartan gravity

Mikhail Chapochnikov, Sebastian Zell

We show how Einstein-Cartan gravity can accommodate both global scale and local scale (Weyl) invariance. To this end, we construct a wide class of models with nonpropagating torsion and a nonminimally coupled scalar field. In phenomenological applications ...

American Physical Society2021

The nu MSM and muon to electron conversion experiments

Mikhail Chapochnikov, Laurent Canetti

We review briefly the different constraints on the three right-handed neutrinos of the nu MSM, an extension of the Standard Model that can explain baryon asymmetry, dark matter and neutrino masses. We include in the discussion the proposed experiments on m ...

Springer Netherlands2013

The role of sterile neutrinos in cosmology and astrophysics

Mikhail Chapochnikov, Alexey Boyarsky, Oleg Ruchayskiy

We present a comprehensive overview of an extension of the Standard Model that contains three right-handed (sterile) neutrinos with masses below the electroweak scale [the Neutrino Minimal Standard Model (vMSM)]. We consider the history of the Universe fro ...

Annual Reviews2009

Scale invariant Einstein-Cartan gravity and flat space conformal symmetry

Mikhail Chapochnikov, Georgios Karananas, Sebastian Zell

We find the conditions under which scale-invariant Einstein-Cartan gravity with scalar matter fields leads to an approximate conformal invariance of the flat space particle theory up to energies of the order of the Planck mass. In the minimal setup, these ...

Springer Nature2023

The masses of active neutrinos in the nuMSM from X-ray astronomy

Mikhail Chapochnikov, Alexey Boyarsky, Oleg Ruchayskiy

In an extension of the Standard Model by three relatively light right-handed neutrinos (the νMSM model) the role of the dark matter particle is played by the lightest sterile neutrino. We demonstrate that the observations of the extragalactic x-ray backgro ...

2006

Reconstruction of 400 GeV/c proton interactions with the SHiP-charm project

Mikhail Chapochnikov, Alexandre Emmanuel Grandchamp, Lesya Shchutska, Inar Timiryasov, Maria Elena Stramaglia, Ana Bárbara Rodrigues Cavalcante, Federico Leo Redi, Elena Graverini, Erwan Harris Tomi Tagne

The SHiP-charm project was proposed to measure the associated charm production induced by 400 GeV/c protons in a thick target, including the contribution from cascade production. An optimisation run was performed in July 2018 at CERN SPS using a hybrid set ...

2024

Baryon asymmetry of the universe and neutrinos

Mikhail Chapochnikov

Our Universe is charge-asymmetric: it contains no antimatter in amounts comparable to matter. This fact provides cosmological evidence for the nonconservation of baryon number as well as for C and CP breaking. We review the problem of the matter-antimatter ...

2009

Exact quantum conformal symmetry, its spontaneous breakdown, and gravitational Weyl anomaly

Mikhail Chapochnikov, Anna Tokareva

The classical Lagrangian of the Standard Model enjoys the symmetry of the full conformal group if the mass of the Higgs boson is put to zero. This is a hint that conformal symmetry may play a fundamental role in the ultimate theory describing nature. The o ...

American Physical Society2023

Measurement of the muon flux at the SND@LHC experiment

Aurelio Bay, Mikhail Chapochnikov, Guido Haefeli, Olivier Schneider, Lesya Shchutska, Paul Théodore Gabriel Pablo De Bryas Dexmiers d'Archiac, Anna Mascellani, Carina Trippl, Serhii Cholak, Elena Graverini, Ettore Zaffaroni, Anni Matilda Kauniskangas, Federico Ronchetti

The Scattering and Neutrino Detector at the LHC (SND@LHC) started taking data at the beginning of Run 3 of the LHC. The experiment is designed to perform measurements with neutrinos produced in proton-proton collisions at the LHC in an energy range between ...

2024

The nuMSM, dark matter and baryon asymmetry of the universe

Mikhail Chapochnikov

We show that the extension of the standard model by three right-handed neutrinos with masses smaller than the electroweak scale (the νMSM) can explain simultaneously dark matter and baryon asymmetry of the universe and be consistent with the experiments on ...

2005

Spontaneously broken scale invariance and minimal fields of canonical dimensionality

Mikhail Chapochnikov, Alexander Monin

We address the question whether a scale invariant theory can contain interacting minimal fields of canonical dimensionality. It is known that the answer to this question is negative provided the scale symmetry is respected by the ground state. We present a ...

American Physical Society2013

Late and early time phenomenology of Higgs-dependent cutoff

Mikhail Chapochnikov

The analysis of theories with non-minimal coupling of Higgs field to gravity revealed that they enter into strong coupling regime above certain Higgs-dependent cutoff, which may be considerably below the Planck scale. Assuming that the effective theory, co ...

2011