Dark-Sector Search via Pion-Produced η and η0 Mesons Decaying Invisibly in the NA64h Detector

Andreev, Yu.M.; Soto, O.; Krasnikov, N.V.; Lyubovitskij, V.E.; Volkov, P.V.; Girod, S.; Depero, E.; Salamatin, K.M.; Tikhomirov, V.O.; Kambar, Y.; Bernhard, J.; Antonov, A.; Enik, T.; Sieber, H.; Mena Yanssen, R.G.; Ketzer, B.; Frolov, V.N.; Mena Fredes, R.; Kachanov, V.A.; Kekelidze, G.D.; Samoylenko, V.D.; Kuleshov, S.V.; Bisio, P.; Kravchuk, L.V.; Tlisova, I.V.; Mongillo, M.; Ayala Torres, M.A.; Shchukin, D.A.; Kolosov, V.N.; Matveev, V.A.; Voronchikhin, I.V.; Crivelli, P.; Hösgen, M.; Zhevlakov, A.S.; Radics, B.; Donskov, S.V.; Celentano, A.; Banto Oberhauser, B.; Kirsanov, M.M.; Toropin, A.N.; Marsicano, L.; Karneyeu, A.E.; Kramarenko, V.A.; Molina Bueno, L.; Dermenev, A.V.; Tuzi, M.; Polyakov, V.A.; Zamora-Saá, J.; Charitonidis, N.; Banerjee, D.; Kirpichnikov, D.V.; Dusaev, R.R.; Gertsenberger, S.V.; Gninenko, S.N.; Marini, A.; Volkov, V.Yu.; Cooke, D.; Peshekhonov, D.V.

doi:10.1103/PhysRevLett.133.121803

Article
Report number	arXiv:2406.01990 ; CERN-EP-2024-153
Title	Dark-Sector Search via Pion-Produced η and η0 Mesons Decaying Invisibly in the NA64h Detector
Related title	50 GeV π− in, nothing out: a sensitive probe of invisible η and η′ decays with NA64h
Author(s)	Andreev, Yu.M. (Unlisted) ; Antonov, A. (INFN, Genoa) ; Ayala Torres, M.A. (Andres Bello Natl. U. ; SAPHIR Millennium Inst. ; Unlisted, CL ; Chile U., Santiago) ; Banerjee, D. (CERN) ; Banto Oberhauser, B. (Zurich, ETH) ; Bernhard, J. (CERN) ; Bisio, P. (INFN, Genoa ; U. Genoa) ; Celentano, A. (INFN, Genoa) ; Charitonidis, N. (CERN) ; Cooke, D. (University Coll. London) ; Crivelli, P. (Zurich, ETH) ; Depero, E. (Zurich, ETH) ; Dermenev, A.V. (Unlisted) ; Donskov, S.V. (Unlisted) ; Dusaev, R.R. (Unlisted) ; Enik, T. (Unlisted) ; Frolov, V.N. (Unlisted) ; Gertsenberger, S.V. (Unlisted) ; Girod, S. (CERN) ; Gninenko, S.N. (Unlisted ; SAPHIR Millennium Inst. ; Chile U., Santiago) ; Hösgen, M. (Bonn U., HISKP) ; Kachanov, V.A. (Unlisted) ; Kambar, Y. (Unlisted) ; Karneyeu, A.E. (Unlisted) ; Kekelidze, G.D. (Unlisted) ; Ketzer, B. (Bonn U., HISKP) ; Kirpichnikov, D.V. (Unlisted) ; Kirsanov, M.M. (Unlisted) ; Kolosov, V.N. (Unlisted) ; Kramarenko, V.A. (Unlisted) ; Kravchuk, L.V. (Unlisted) ; Krasnikov, N.V. (Unlisted) ; Kuleshov, S.V. (Andres Bello Natl. U. ; SAPHIR Millennium Inst. ; Unlisted, CL ; Chile U., Santiago) ; Lyubovitskij, V.E. (Unlisted ; Santa Maria U., Valparaiso ; SAPHIR Millennium Inst. ; Chile U., Santiago) ; Marini, A. (INFN, Genoa) ; Marsicano, L. (INFN, Genoa) ; Matveev, V.A. (Unlisted) ; Mena Fredes, R. (SAPHIR Millennium Inst. ; Santa Maria U., Valparaiso ; Chile U., Santiago) ; Mena Yanssen, R.G. (SAPHIR Millennium Inst. ; Santa Maria U., Valparaiso ; Chile U., Santiago) ; Molina Bueno, L. (Valencia U., IFIC) ; Mongillo, M. (Zurich, ETH) ; Peshekhonov, D.V. (Unlisted) ; Polyakov, V.A. (Unlisted) ; Radics, B. (York U., Toronto (main)) ; Salamatin, K.M. (Unlisted) ; Samoylenko, V.D. (Unlisted) ; Sieber, H. (Zurich, ETH) ; Shchukin, D.A. (Unlisted) ; Soto, O. (La Serena U. ; SAPHIR Millennium Inst. ; Chile U., Santiago) ; Tikhomirov, V.O. (Unlisted) ; Tlisova, I.V. (Unlisted) ; Toropin, A.N. (Unlisted) ; Tuzi, M. (Valencia U., IFIC) ; Volkov, P.V. (Unlisted) ; Volkov, V.Yu. (Unlisted) ; Voronchikhin, I.V. (Unlisted) ; Zamora-Saá, J. (Andres Bello Natl. U. ; SAPHIR Millennium Inst. ; Unlisted, CL ; Chile U., Santiago) ; Zhevlakov, A.S. (Unlisted)
Publication	2024-09-20
Imprint	30 May 2024
Number of pages	6
Note	5 pages, 3 figures
In:	Phys. Rev. Lett. 133 (2024) 121803
DOI	10.1103/PhysRevLett.133.121803 (publication)
Subject category	Nuclear Physics - Experiment ; Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN SPS ; NA64
Free keywords	exotics ; rare decay ; experimental results ; Invisible decays neutral meson
Abstract	We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar η and η′ mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV π− on nuclei of an active target as the source of neutral mesons. The η, η′ → invisible events would exhibit themselves via a striking signature - the complete disappearance of the incoming beam energy in the detector. No evidence for such events has been found with 2.9 × 109 pions on target accumulated during one day of data taking. This allows us to set a stringent limit on the branching ratio Br(η′ → invisible) < 2.1 × 10−4 improving the current bound by a factor of ≃ 3. We also set a limit on Br(η → invisible) < 1.1 × 10−4 comparable with the existing one. These results demonstrate the great potential of our approach and provide clear guidance on how to enhance and extend the sensitivity for dark sector physics from future searches for invisible neutral meson decays.
Copyright/License	preprint: © 2024-2025 CERN (License: CC-BY-4.0) publication: © 2024-2025 The author(s) (License: CC BY 4.0), sponsored by SCOAP³

$Diagrams illustrating the $\eta$ production in the quasi-elastic charge exchange reaction of Eq.(\ref{eq:etaprod}).$

$The measured distribution of the total energy deposited in three HCAL modules (HCAL1+HCAL2+HCAL3) with signal selection cuts applied, i.e for events with the energy deposited in Veto $E_{VETO}\lesssim 2$ MeV. The expected total background contributions (solid black) are overlaid on the data (points) from the shaded area. The peak at $\sim 2.5$ GeV (dashed blue) corresponds to the background component due to backward muons from $K^- \to \mu^- \bar\nu_\mu $ decays, the smooth background above $\gtrsim 3$ GeV is the energy deposited in the HCAL by poorly vetoed muons from $K^- \to \mu^- \bar\nu_\mu $ decaying forward. The shape of the expected signal distribution from the $\eta \to invisible$ decay (solid blue) is normalized to ten signal events. For the $\eta' \to invisible$ the signal shape is very similar.$ Show more plots

Corresponding record in: Inspire
Email contact: [email protected]

Naspäť k hľadaniu

Záznam vytvorený 2024-05-30, zmenený 2025-06-06

Plný text: