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Kovalenko, Sergey
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Kovalenko, Sergey
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Campus / Sede
Campus Casa Central Valparaíso
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Scopus Author ID
7101988084
Now showing 1 - 10 of 19
- PublicationThe experimental facility for the Search for Hidden Particles at the CERN SPS(2019-03-25)
;Ahdida, C. ;Albanese, R. ;Alexandrov, A. ;Anokhina, A. ;Aoki, S. ;Arduini, G. ;Atkin, E. ;Azorskiy, N. ;Back, J. J. ;Bagulya, A. ;Santos, F. Baaltasar Dos ;Baranov, A. ;Bardou, F. ;Barker, G. J. ;Battistin, M. ;Bauche, J. ;Bay, A. ;Bayliss, V. ;Bencivenni, G. ;Berdnikov, A. Y. ;Berdnikov, Y. A. ;Berezkina, I. ;Bertani, M. ;Betancourt, C. ;Bezshyiko, I. ;Bezshyyko, O. ;Bick, D. ;Bieschke, S. ;Blanco, A. ;Boehm, J. ;Bogomilov, M. ;Bondarenko, K. ;Bonivento, W. M. ;Borburgh, J. ;Boyarsky, A. ;Brenner, R. ;Breton, D. ;Brundler, R. ;Bruschi, M. ;Büscher, V. ;Buonaura, A. ;Buontempo, S. ;Cadeddu, S. ;Calcaterra, A. ;Calviani, M. ;Campanelli, M. ;Casolino, M. ;Charitonidis, N. ;Chau, P. ;Chauveau, J. ;Chepurnov, A. ;Chernyavskiy, M. ;Choi, K. Y. ;Chumakov, A. ;Ciambrone, P. ;Cornelis, K. ;Cristinziani, M. ;Crupano, A. ;Dallavalle, G. M. ;Datwyler, A. ;D'ambrosio, N. ;D'appollonio, G. ;Saraiva, J. De Carvalho ;Lellis, G. De ;De Magistris, M. ;Roeck, A. De ;De Serio, M. ;De Simone, D. ;Dedenko, L. ;Dergachev, P. ;Di Crescenzo, A. ;Di Marco, N.; ;Dmitrievskiy, S. ;Dougherty, L. A. ;Dolmatov, A. ;Domenici, D. ;Donskov, S. ;Drohan, V. ;Dubreuil, A. ;Ebert, J. ;Enik, T. ;Etenko, A. ;Fabbri, F. ;Fabbri, L. ;Fabich, A. ;Fedin, O. ;Fedotovs, F. ;Felici, G. ;Ferro-Luzzi, M. ;Filippov, K. ;Fini, R. A. ;Fonte, P. ;Franco, C. ;V. Lyubovitskij; Froeschl, R.The Search for Hidden Particles (SHiP) Collaboration has shown that the CERN SPS accelerator with its 400 GeV c proton beam offers a unique opportunity to explore the Hidden Sector [1–3]. The proposed experiment is an intensity frontier experiment which is capable of searching for hidden particles through both visible decays and through scattering signatures from recoil of electrons or nuclei. The high-intensity experimental facility developed by the SHiP Collaboration is based on a number of key features and developments which provide the possibility of probing a large part of the parameter space for a wide range of models with light long-lived superweakly interacting particles with masses up to O¹10º GeV c2 in an environment of extremely clean background conditions. This paper describes the proposal for the experimental facility together with the most important feasibility studies. The paper focuses on the challenging new ideas behind the beam extraction and beam delivery, the proton beam dump, and the suppression of beam-induced background. - PublicationNew aspects of muon-electron nuclear conversion(2002-09-19)
;Šimkovic, F.; ;Gutsche, Th ;Faessler, AmandWe found a new important tree-level contribution to muon–electron nuclear conversion from neutrino exchange between two quarks in the same nucleon and demonstrated that this process, contrary to common belief, can be observed in the near future experiments if there exists a mixed sterile-active neutrino state νh heavier than the quark confinement scale Λc ∼ 1 GeV. From the present non-observation of muon–electron conversion we derive new experimental constraints on νh − νe,µ mixing - PublicationDark matter from a radiative inverse seesaw majoron model(2023-12-10)
;Bonilla, Cesar; ;Díaz Sáez, Bastián; Marchant González, JuanWe propose a Majoron-like extension of the Standard Model with an extra global -symmetry where neutrino masses are generated through an inverse seesaw mechanism at the 1-loop level. In contrast to the tree-level inverse seesaw, our framework contains dark matter (DM) candidates stabilized by a residual -symmetry surviving spontaneous breaking of the -group. We explore the case in which the DM is a Majorana fermion. Furthermore, we provide parameter space regions allowed by current experimental constraints coming from the dark matter relic abundance, (in)direct detection, and charged lepton flavor violation. - PublicationRadiative type-I seesaw neutrino masses(2019-12-09)
; ; ;Cepedello, Ricardo ;Hirsch, MartinWe discuss a radiative type-I seesaw. In these models, the radiative generation of Dirac neutrino masses allows to explain the smallness of the observed neutrino mass scale for rather light right-handed neutrino masses in a type-I seesaw. We first present the general idea in a model-independent way. This allows us to estimate the typical scale of right-handed neutrino mass as a function of the number of loops. We then present two example models, at the one- and two-loop level, which we use to discuss neutrino masses and lepton-flavor-violating constraints in more detail. For the two-loop example, right-handed neutrino masses must lie below 100 GeV, thus making this class of models testable in heavy neutral lepton searches. - PublicationDark Matter Search in Missing Energy Events with NA64(2019-09-18)
;Banerjee, D. ;Burtsev, V. E. ;Cooke, D. ;Crivelli, P. ;Depero, E. ;Dermenev, A. V. ;Donskov, S. V. ;Dusaev, R. R. ;Enik, T. ;Charitonidis, N. ;Feshchenko, A. ;Frolov, V. N. ;Gardikiotis, A. ;Gerassimov, S. G. ;Gninenko, S. N. ;Hösgen, M. ;Jeckel, M. ;Karneyeu, A. E. ;Kekelidze, G. ;Ketzer, B. ;Kirpichnikov, D. V. ;Kirsanov, M. M. ;Konorov, I. V.; ;Kramarenko, V. A. ;Kravchuk, L. V. ;Krasnikov, N. V. ;Kuleshov, S. V.; ;Lysan, V. ;Matveev, V. A. ;Mikhailov, Yu V. ;Molina Bueno, L. ;Peshekhonov, D. V. ;Polyakov, V. A. ;Radics, B.; ;Rubbia, A. ;Samoylenko, V. D. ;Shchukin, D. ;Tikhomirov, V. O. ;Tlisova, I. ;Tlisov, D. A. ;Toropin, A. N. ;Trifonov, A. Yu ;Vasilishin, B. I. ;Vasquez Arenas, G. ;Volkov, P. V. ;Volkov, V. YuUlloa, P.A search for sub-GeV dark matter production mediated by a new vector boson A′, called dark photon, is performed by the NA64 experiment in missing energy events from 100 GeV electron interactions in an active beam dump at the CERN SPS. From the analysis of the data collected in the years 2016, 2017, and 2018 with 2.84×1011 electrons on target no evidence of such a process has been found. The most stringent constraints on the A′ mixing strength with photons and the parameter space for the scalar and fermionic dark matter in the mass range ≲0.2 GeV are derived, thus demonstrating the power of the active beam dump approach for the dark matter search. - PublicationErratum: QCD running in neutrinoless double beta decay: Short-range mechanisms (Physical Review D (2016) 93 (013017) DOI: 10.1103/PhysRevD.93.013017)(2018-05-01)
;M. González; M. HirschThe decay rate of neutrinoless double beta (0νββ) decay contains terms from heavy particle exchange, which lead to dimension-9 (d ¼ 9) six fermion operators at low energies. Limits on the coefficients of these operators have been derived previously neglecting the running of the operators between the high scale, where they are generated, and the energy scale of 0νββ decay, where they are measured. Here we calculate the leading-order QCD corrections to all possible d ¼ 9 operators contributing to the 0νββ amplitude and use renormalization group running to calculate 1-loop improved limits. Numerically, QCD running dramatically changes some limits by factors of the order of or larger than typical uncertainties in nuclear matrix element calculations. For some specific cases, operator mixing in the running changes limits even by up to 3 orders of magnitude. Our results can be straightforwardly combined with new experimental limits or improved nuclear matrix element calculations to rederive updated limits on all short-range contributions to 0νββ decay. - PublicationSearch for a Hypothetical 16.7 MeV Gauge Boson and Dark Photons in the NA64 Experiment at CERN(2018-06-08)
;Banerjee, D. ;Burtsev, V. E. ;Chumakov, A. G. ;Cooke, D. ;Crivelli, P. ;Depero, E. ;Dermenev, A. V. ;Donskov, S. V. ;Dusaev, R. R. ;Enik, T. ;Charitonidis, N. ;Feshchenko, A. ;Frolov, V. N. ;Gardikiotis, A. ;Gerassimov, S. G. ;Gninenko, S. N. ;Hösgen, M. ;Jeckel, M. ;Karneyeu, A. E. ;Kekelidze, G. ;Ketzer, B. ;Kirpichnikov, D. V. ;Kirsanov, M. M. ;Konorov, I. V.; ;Kramarenko, V. A. ;Kravchuk, L. V. ;Krasnikov, N. V.; ; ;Lysan, V. ;Matveev, V. A. ;Mikhailov, Yu V. ;Peshekhonov, D. V. ;Polyakov, V. A. ;Radics, B. ;Rojas, R. ;Rubbia, A. ;Samoylenko, V. D. ;Tikhomirov, V. O. ;Tlisov, D. A. ;Toropin, A. N. ;Trifonov, A. Yu ;Vasilishin, B. I. ;Vasquez Arenas, G. ;Volkov, P. V. ;Volkov, V.Ulloa, P.We report the first results on a direct search for a new 16.7 MeV boson (X) which could explain the anomalous excess of eþe− pairs observed in the excited 8 Be nucleus decays. Because of its coupling to electrons, the X could be produced in the bremsstrahlung reaction e−Z → e−ZX by a 100 GeV e− beam incident on an active target in the NA64 experiment at the CERN Super Proton Synchrotron and observed through the subsequent decay into a eþe− pair. With 5.4 × 1010 electrons on target, no evidence for such decays was found, allowing us to set first limits on the X − e− coupling in the range 1.3 × 10−4 ≲ ϵe ≲ 4.2 × 10−4 excluding part of the allowed parameter space. We also set new bounds on the mixing strength of photons with dark photons (A0 ) from nonobservation of the decay A0 → eþe− of the bremsstrahlung A0 with a mass ≲23 MeV - PublicationProbing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel(2021-10-01)
;Cazzaniga, C. ;Odagiu, P. ;Depero, E. ;Molina Bueno, L. ;Andreev, Yu M. ;Banerjee, D. ;Bernhard, J. ;Burtsev, V. E. ;Charitonidis, N. ;Chumakov, A. G. ;Cooke, D. ;Crivelli, P. ;Dermenev, A. V. ;Donskov, S. V. ;Dusaev, R. R. ;Enik, T. ;Feshchenko, A. ;Frolov, V. N. ;Gardikiotis, A. ;Gerassimov, S. G. ;Girod, S. ;Gninenko, S. N. ;Hösgen, M. ;Kachanov, V. A. ;Karneyeu, A. E. ;Kekelidze, G. ;Ketzer, B. ;Kirpichnikov, D. V. ;Kirsanov, M. M. ;Kolosov, V. N. ;Konorov, I. V.; ;Kramarenko, V. A. ;Kravchuk, L. V. ;Krasnikov, N. V.; ; ;Lysan, V. ;Matveev, V. A. ;Mikhailov, Yu V. ;Peshekhonov, D. V. ;Polyakov, V. A. ;Radics, B. ;Rojas, R. ;Rubbia, A. ;Samoylenko, V. D. ;Shchukin, D. ;Sieber, H. ;Tikhomirov, V. O. ;Tlisova, I. V. ;Tlisov, D. A. ;Toropin, A. N. ;Trifonov, A. Yu ;Vasilishin, B. I. ;Arenas, G. Vasquez ;Volkov, P. V. ;Volkov, V. YuUlloa, P.AbstractWe report the results of a search for a new vector boson ($$ A'$$ A ′ ) decaying into two dark matter particles $$\chi _1 \chi _2$$ χ 1 χ 2 of different mass. The heavier $$\chi _2$$ χ 2 particle subsequently decays to $$\chi _1$$ χ 1 and an off-shell Dark Photon $$ A'^* \rightarrow e^+e^-$$ A ′ ∗ → e + e - . For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab. Remarkably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained re-analyzing the previous NA64 searches for an invisible decay $$A'\rightarrow \chi \overline{\chi }$$ A ′ → χ χ ¯ and axion-like or pseudo-scalar particles $$a \rightarrow \gamma \gamma $$ a → γ γ . With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for $$A'$$ A ′ masses from 2$$m_e$$ m e up to 390 MeV and mixing parameter $$\varepsilon $$ ε between $$3\times 10^{-5}$$ 3 × 10 - 5 and $$2\times 10^{-2}$$ 2 × 10 - 2 . - PublicationSequentially loop-generated quark and lepton mass hierarchies in an extended Inert Higgs Doublet model(2019-06-01)
; ;Pasechnik, Roman; Abstract Extended scalar and fermion sectors offer new opportunities for generating the observed strong hierarchies in the fermion mass and mixing patterns of the Standard Model (SM). In this work, we elaborate on the prospects of a particular extension of the Inert Higgs doublet model where the SM hierarchies are generated sequentially by radiative virtual corrections in a fully renormalisable way, i.e. without adding any non-renormalisable Yukawa terms or soft-breaking operators to the scalar potential. Our model has a potential to explain the recently observed R K and R K∗ anomalies, thanks to the non universal U1X assignments of the fermionic fields that yield non universal Z′ couplings to fermions. We explicitly demonstrate the power of this model for generating the realistic quark, lepton and neutrino mass spectra. In particular, we show that due to the presence of both continuous and discrete family symmetries in the considered framework, the top quark acquires a tree-level mass, lighter quarks and leptons get their masses at one- and two-loop order, while neutrino masses are generated at three-loop level. The minimal field content, particle spectra and scalar potential of this model are discussed in detail. - PublicationSearch for vector mediator of dark matter production in invisible decay mode(2018-04-01)
;Banerjee, D. ;Burtsev, V. E. ;Chumakov, A. G. ;Cooke, D. ;Crivelli, P. ;Depero, E. ;Dermenev, A. V. ;Donskov, S. V. ;Dubinin, F. ;Dusaev, R. R. ;Emmenegger, S. ;Fabich, A. ;Frolov, V. N. ;Gardikiotis, A. ;Gerassimov, S. G. ;Gninenko, S. N. ;Hösgen, M. ;Karneyeu, A. E. ;Ketzer, B. ;Kirpichnikov, D. V. ;Kirsanov, M. M. ;Konorov, I. V.; ;Kramarenko, V. A. ;Kravchuk, L. V. ;Krasnikov, N. V.; ; ;Lysan, V. ;Matveev, V. A. ;Mikhailov, Yu V. ;Peshekhonov, D. V. ;Polyakov, V. A. ;Radics, B. ;Rojas, R. ;Rubbia, A. ;Samoylenko, V. D. ;Tikhomirov, V. O. ;Tlisov, D. A. ;Toropin, A. N. ;Trifonov, A. Yu ;Vasilishin, B. I. ;Vasquez Arenas, G.Ulloa, P.A search is performed for a new sub-GeV vector boson (A0 ) mediated production of dark matter (χ) in the fixed-target experiment, NA64, at the CERN SPS. The A0 , called dark photon, can be generated in the reaction e−Z → e−ZA0 of 100 GeV electrons dumped against an active target followed by its prompt invisible decay A0 → χχ¯. The experimental signature of this process would be an event with an isolated electron and large missing energy in the detector. From the analysis of the data sample collected in 2016 corresponding to 4.3 × 1010 electrons on target no evidence of such a process has been found. New stringent constraints on the A0 mixing strength with photons, 10−5 ≲ ϵ ≲ 10−2, for the A0 mass range mA0 ≲ 1 GeV are derived. For models considering scalar and fermionic thermal dark matter interacting with the visible sector through the vector portal the 90% C.L. limits 10−11 ≲ y ≲ 10−6 on the dark-matter parameter y ¼ ϵ2αDð mχ mA0 Þ4 are obtained for the dark coupling constant αD ¼ 0.5 and dark-matter masses 0.001 ≲ mχ ≲ 0.5 GeV. The lower limits αD ≳ 10−3 for pseudo-Dirac dark matter in the mass region mχ ≲ 0.05 GeV are more stringent than the corresponding bounds from beam dump experiments. The results are obtained by using exact tree level calculations of the A0 production cross sections, which turn out to be significantly smaller compared to the one obtained in the Weizsäcker-Williams approximation for the mass region mA0 ≳ 0.1 GeV.