DOI: 10.1140/epjc/s10052-026-16035-x ISSN: 1434-6052

Measurement of the muon flux at SND@LHC

, D. Abbaneo, S. Ahmad, R. Albanese, A. Alexandrov, F. Alicante, F. Aloschi, K. Androsov, A. Anokhina, L. G. Arellano, C. Asawatangtrakuldee, M. A. Ayala Torres, N. Bangaru, C. Battilana, A. Bay, C. Betancourt, D. Bick, R. Biswas, A. Blanco Castro, V. Boccia, M. Bogomilov, D. Bonacorsi, W. M. Bonivento, P. Bordalo, A. Boyarsky, S. Buontempo, T. Camporesi, V. Canale, D. Centanni, F. Cerutti, A. Cervelli, V. Chariton, M. Chernyavskiy, A. Chiuchiolo, K.-Y. Choi, F. Cindolo, M. Climescu, G. M. Dallavalle, N. D’Ambrosio, D. Davino, R. De Asmundis, P. T. de Bryas, G. De Lellis, M. de Magistris, G. Del Guidice, G. De Marzi, A. De Roeck, S. De Pasquale, A. De Rújula, M. A. Diaz Gutierrez, A. Di Crescenzo, C. Di Cristo, D. Di Ferdinando, C. Dinc, I. Dionisov, R. Donà, O. Durhan, D. Fasanella, O. Fecarotta, M. Ferrillo, A. Fiorillo, N. Funicello, R. Fresa, W. Funk, G. Galati, K. Genovese, V. Giordano, A. Golutvin, E. Graverini, C. Guandalini, L. Guiducci, A. M. Guler, V. Guliaeva, G. J. Haefeli, C. Hagner, J. C. Helo Herrera, E. van Herwijnen, S. Ilieva, S. A. Infante Cabanas, A. Infantino, A. Iuliano, A. M. Kauniskangas, E. Khalikov, S. H. Kim, Y. G. Kim, G. Klioutchnikov, M. Komatsu, N. Konovalova, S. Kuleshov, H. M. Lacker, I. Landi, O. Lantwin, F. Lasagni Manghi, A. Lauria, K. Y. Lee, K. S. Lee, W.-C. Lee, V. P. Loschiavo, A. Mascellani, M. Majstorovic, F. Mei, A. Miano, A. Mikulenko, M. C. Montesi, D. Morozova, L. Mozzina, F. L. Navarria, W. Nuntiyakul, K. Obayashi, S. Ogawa, N. Okateva, M. Ovchynnikov, G. Paggi, A. Perrotta, D. Podgrudkov, N. Polukhina, F. Primavera, A. Prota, A. Quercia, S. Ramos, A. Reghunath, T. Roganova, F. Ronchetti, N. Rossolino, T. Rovelli, O. Ruchayskiy, T. Ruf, Z. Sadykov, M. Samoilov, V. Scalera, W. Schmidt-Parzefall, O. Schneider, G. Sekhniaidze, A. Serban, N. Serra, M. Shaposhnikov, V. Shevchenko, T. Shchedrina, L. Shchutska, H. Shibuya, C. Silano, G. P. Siroli, G. Sirri, T. E. Smith, G. Soares, J. Y. Sohn, O. J. Soto Sandoval, M. Spurio, N. Starkov, J. Steggemann, A. Tarek, J. Tesarek, I. Timiryasov, V. Tioukov, C. Trippl, E. Ursov, G. Vankova-Kirilova, G. Vasquez, V. Verguilov, N. Viegas Guerreiro Leonardo, C. Vilela, R. Wanke, S. Yamamoto, Z. Yang, C. Yazici, S. M. Yoo, C. S. Yoon, E. Zaffaroni, J. Zamora Saá

Abstract

The SND@LHC experiment investigates neutrinos in the

$$7.2< \eta < 8.4$$ 7.2 < η < 8.4
forward pseudorapidity range. The detector consists of a veto system, a scintillating fiber tracker interleaved with emulsion cloud chambers, and a downstream muon system. Muons originating from collisions at ATLAS (IP1) constitute the primary background for CC neutrino interactions and determine the replacement frequency of the emulsion target. A precise characterization of this flux is therefore essential. In this work, we report the muon flux measured in the central
$$31 \times 31$$ 31 × 31
$$\textrm{cm}^2$$ cm 2
fiducial area of the detector using data from 2023 through 2025. The measured fluxes for proton collisions are: (1.90±0.04)
$$\times 10^{-2}$$ × 10 - 2
 
$$\text {nb/cm}^{2}$$ nb/cm 2
(2023), (3.76 ± 0.09)
$$\times $$ ×
$$\text {10}^{-2}$$ 10 - 2
 
$$\text {nb/cm}^{2}$$ nb/cm 2
(2024), and (2.48 ± 0.05)
$$\times 10^{-2}$$ × 10 - 2
 
$$\text {nb/cm}^{2}$$ nb/cm 2
(2025). A 2024 reference proton run at
$$\sqrt{s} = 5.36\text { TeV}$$ s = 5.36 TeV
yielded (4.21 ± 0.14)
$$\times $$ ×
$$\text {10}^{-2}$$ 10 - 2
 
$$\text {nb/cm}^{2}$$ nb/cm 2
, providing a direct baseline for the heavy-ion energy regime. The measured fluxes for heavy-ion collisions are (3.11±0.12)
$$\times \text {10}^{4}$$ × 10 4
 
$$\text {nb/cm}^{2}$$ nb/cm 2
, (5.53±0.22)
$$\times 10^{4}$$ × 10 4
 
$$\text {nb/cm}^{2}$$ nb/cm 2
, and (3.24±0.13)
$$\times \text {10}^{4}$$ × 10 4
$$\text {nb/cm}^{2}$$ nb/cm 2
in 2023, 2024, and 2025, respectively. Uncertainties are dominated by systematic effects, with the statistical component contributing
$$\lesssim $$
0.1% to the total uncertainty. These results are in agreement with Monte Carlo predictions.

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