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26 results on '"Gritsay, K."'

1. The \pi^+\pi^- Coulomb interaction study and its use in the data processing

Author

Adeva, B., Afanasyev, L., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Drijard, D., Dudarev, A., Dumitriu, D., Federicova, P., Gorin, A., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Kluson, J., Kobayashi, M., Kruglova, L., Kulikov, A., Kulish, E., Lamberto, A., Lanaro, A., Lednicky, R., Marinas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., and Zrelov, P.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment
Abstract

In this work the Coulomb effects (Coulomb correlations) in $\pi^+\pi^-$ pairs produced in p + Ni collisions at 24 GeV/$c$, are studied using experimental $\pi^+\pi^-$ pair distributions in $Q$, the relative momentum in the pair center of mass system (c.m.s), and its projections $Q_L$ (longitudinal component) and $Q_t$ (transverse component) relative to the pair direction in the laboratory system (l.s.). The $Q$, $Q_L$, and $Q_t$ distributions of the {\sl Coulomb pairs} in the c.m.s. have been simulated assuming they are described by the phase space modified by the known point-like Coulomb correlation function $A_C(Q)$, corrected for small effects due to the nonpoint-like pair production and the strong two-pion interaction. The same distributions of {\sl non-Coulomb pairs} have been simulated according to the phase space, but without $A_C(Q)$. It is shown that the number of {\sl Coulomb pairs} in all $Q_t$ intervals, including the small $Q_t$ (small opening angles $\theta$ in the l.s.) is calculated with the theoretical precision better than 2\%. The comparison of the simulated and experimental numbers of {\sl Coulomb pairs} at small $Q_t$ allows us to check and correct the detection efficiency for the pairs with small $\theta$ (0.06 mrad and smaller). It is shown that {\sl Coulomb pairs} can be used as a new physical tool to check and correct the quality of the simulated events. The special property of the {\sl Coulomb pairs} is the possibility of checking and correcting the detection efficiency, especially for the pairs with small opening angles.

Published
2024

2. Technical Design Report of the Spin Physics Detector at NICA

Author

The SPD Collaboration, Abazov, V., Abramov, V., Afanasyev, L., Akhunzyanov, R., Akindinov, A., Alekseev, I., Aleshko, A., Alexakhin, V., Alexeev, G., Alimov, L., Allakhverdieva, A., Amoroso, A., Andreev, V., Andronov, E., Anikin, Yu., Anischenko, S., Anisenkov, A., Anosov, V., Antokhin, E., Antonov, A., Antsupov, S., Anufriev, A., Asadova, K., Ashraf, S., Astakhov, V., Aynikeev, A., Azarkin, M., Azorskiy, N., Bagulya, A., Baigarashev, D., Baldin, A., Baldina, E., Barbashina, N., Barnyakov, A., Barsov, S., Bartkevich, A., Baryshevsky, V., Basharina, K., Baskakov, A., Baskov, V., Batista, M., Baturitsky, M., Bautin, V., Bedareva, T., Belokurova, S., Belova, A., Belyaeva, E., Berdnikov, A., Berdnikov, Ya., Berezhnoy, A., Berngardt, A., Bespalov, Yu., Bleko, V., Bliznyuk, L., Bogoslovskii, D., Boiko, A., Boikov, A., Bolsunovskya, M., Boos, E., Borisov, V., Borsch, V., Budkouski, D., Bulanova, S., Bulekov, O., Bunichev, V., Burtebayev, N., Bychanok, D., Casanova, A., Cesar, G., Chemezov, D., Chepurnov, A., Chen, L., Chmill, V., Chukanov, A., Chuzo, A., Danilyuk, A., Datta, A., Dedovich, D., Demichev, M., Deng, G., Denisenko, I., Denisov, O., Derbysheva, T., Derkach, D., Didorenko, A., Dima, M. -O., Doinikov, A., Doronin, S., Dronik, V., Dubinin, F., Dunin, V., Durum, A., Egorov, A., El-Kholy, R., Enik, T., Ermak, D., Erofeev, D., Erokhin, A., Ezhov, D., Fedin, O., Fedotova, Ju., Feofilov, G., Filatov, Yu., Filimonov, S., Frolov, V., Galaktionov, K., Galoyan, A., Garkun, A., Gavrishchuk, O., Gerasimov, S., Gerassimov, S., Gilts, M., Gladilin, L., Golovanov, G., Golovnya, S., Golovtsov, V., Golubev, A., Golubykh, S., Goncharov, P., Gongadze, A., Greben, N., Gregoryev, A., Gribkov, D., Gridin, A., Gritsay, K., Gubachev, D., Guo, J., Gurchin, Yu., Gurinovich, A., Gurov, Yu., Guskov, A., Gutierrez, D., Guzman, F., Hakobyan, A., Han, D., Harkusha, S., Hu, Sh., Igolkin, S., Isupov, A., Ivanov, A., Ivanov, N., Ivantchenko, V., Jin, Sh., Kakurin, S., Kalinichenko, N., Kambar, Y., Kantsyrev, A., Kapitonov, I., Karjavine, V., Karpishkov, A., Katcin, A., Kekelidze, G., Kereibay, D., Khabarov, S., Kharyuzov, P., Khodzhibagiyan, H., Kidanov, E., Kidanova, E., Kim, V., Kiryanov, A., Kishchin, I., Kokoulina, E., Kolbasin, A., Komarov, V., Konak, A., Kopylov, Yu., Korjik, M., Korotkov, M., Korovkin, D., Korzenev, A., Kostenko, B., Kotova, A., Kotzinian, A., Kovalenko, V., Kovyazina, N., Kozhin, M., Kraeva, A., Kramarenko, V., Kremnev, A., Kruchonak, U., Kubankin, A., Kuchinskaia, O., Kulchitsky, Yu., Kuleshov, S., Kulikov, A., Kulikov, V., Kurbatov, V., Kurmanaliev, Zh., Kurochkin, Yu., Kutuzov, S., Kuznetsova, E., Kuyanov, I., Ladygin, E., Ladygin, V., Larionova, D., Lebedev, V., Levchuk, M., Li, P., Li, X., Li, Y., Livanov, A., Lednicki, R., Lobanov, A., Lobko, A., Loshmanova, K., Lukashevich, S., Luschevskaya, E., Lyashko, A. L'vov I., Lysan, V., Lyubovitskij, V., Madigozhin, D., Makarenko, V., Makarov, N., Makhmanazarov, R., Maleev, V., Maletic, D., Malinin, A., Maltsev, A., Maltsev, N., Malkhasyan, A., Malyshev, M., Mamoutova, O., Manakonov, A., Marova, A., Merkin, M., Meshkov, I., Metchinsky, V., Minko, O., Mitrankov, Yu., Mitrankova, M., Mkrtchyan, A., Mkrtchyan, H., Mohamed, R., Morozova, S., Morozikhin, A., Mosolova, E., Mossolov, V., Movchan, S., Mukhamejanov, Y., Mukhamejanova, A., Muzyaev, E., Myktybekov, D., Nagorniy, S., Nassurlla, M., Nechaeva, P., Negodaev, M., Nesterov, V., Nevmerzhitsky, M., Nigmatkulov, G., Nikiforov, D., Nikitin, V., Nikolaev, A., Oleynik, D., Onuchin, V., Orlov, I., Orlova, A., Ososkov, G., Panzieri, D., Parsamyan, B., Pavzderin, P., Pavlov, V., Pedraza, M., Perelygin, V., Peshkov, D., Petrosyan, A., Petrov, M., Petrov, V., Petrukhin, K., Piskun, A., Pivovarov, S., Polishchuk, I., Polozov, P., Polyanskii, V., Ponomarev, A., Popov, V., Popovich, S., Prokhorova, D., Prokofiev, N., Prokoshin, F., Puchkov, A., Pudin, I., Pyata, E., Ratnikov, F., Rasin, V., Red'kov, V., Reshetin, A., Reznikov, S., Rogacheva, N., Romakhov, S., Rouba, A., Rudnev, V., Rusinov, V., Rusov, D., Ryltsov, V., Saduyev, N., Safonov, A., Sakhiyev, S., Salamatin, K., Saleev, V., Samartsev, A., Samigullin, E., Samoylov, O., Saprunov, E., Savenkov, A., Seleznev, A., Semak, A., Senkov, D., Sergeev, A., Seryogin, L., Seryubin, S., Shabanov, A., Shahinyan, A., Shavrin, A., Shein, I., Sheremeteva, A., Shevchenko, V., Shilyaev, K., Shimansky, S., Shinbulatov, S., Shipilov, F., Shipilova, A., Shkarovskiy, S., Shoukovy, D., Shpakov, K., Shreyber, I., Shtejer, K., Shulyakovsky, R., Shunko, A., Sinelshchikova, S., Skachkova, A., Skalnenkov, A., Smirnov, A., Smirnov, S., Snesarev, A., Solin, A., Solin jr., A., Soldatov, E., Solovtsov, V., Song, J., Sosnov, D., Stavinskiy, A., Stekacheva, D., Streletskaya, E., Strikhanov, M., Suarez, O., Sukhikh, A., Sukhovarov, S., Sulin, V., Sultanov, R., Sun, P., Svirida, D., Syresin, E., Tadevosyan, V., Tarasov, O., Tarkovsky, E., Tchekhovsky, V., Tcherniaev, E., Terekhin, A., Terkulov, A., Tereshchenko, V., Teryaev, O., Teterin, P., Tishevsky, A., Tokmenin, V., Topilin, N., Tsiareshka, P., Tumasyan, A., Tyumenkov, G., Usenko, E., Uvarov, L., Uzhinsky, V., Uzikov, Yu., Valiev, F., Vasilieva, E., Vasyukov, A., Vechernin, V., Verkheev, A., Vertogradov, L., Vertogradova, Yu., Vidal, R., Voitishin, N., Volkov, I., Volkov, P., Vorobyov, A., Voskanyan, H., Wang, H., Wang, Y., Xu, T., Yanovich, A., Yeletskikh, I., Yerezhep, N., Yurchenko, S., Zakharov, A., Zamiatin, N., Zamora-Saá, J., Zarochentsev, A., Zelenov, A., Zemlyanichkina, E., Zhabitsky, M., Zhang, J., Zhang, Zh., Zhemchugov, A., Zherebchevsky, V., Zhevlakov, A., Zhigareva, N., Zhou, J., Zhuang, X., Zhukov, I., Zhuravlev, N., Zinin, A., Zmeev, S., Zolotykh, D., Zubarev, E., and Zvyagina, A.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

The Spin Physics Detector collaboration proposes to install a universal detector in the second interaction point of the NICA collider under construction (JINR, Dubna) to study the spin structure of the proton and deuteron and other spin-related phenomena using a unique possibility to operate with polarized proton and deuteron beams at a collision energy up to 27 GeV and a luminosity up to $10^{32}$ cm$^{-2}$ s$^{-1}$. As the main goal, the experiment aims to provide access to the gluon TMD PDFs in the proton and deuteron, as well as the gluon transversity distribution and tensor PDFs in the deuteron, via the measurement of specific single and double spin asymmetries using different complementary probes such as charmonia, open charm, and prompt photon production processes. Other polarized and unpolarized physics is possible, especially at the first stage of NICA operation with reduced luminosity and collision energy of the proton and ion beams. This document is dedicated exclusively to technical issues of the SPD setup construction.

Published
2024

3. Investigation of $K^+K^-$ pairs in the effective mass region near $2m_K$

Author

Adeva, B., Afanasyev, L., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Drijard, D., Dudarev, A., Dumitriu, D., Federicova, P., Gorin, A., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglova, L., Kulikov, A., Kulish, E., Lamberto, A., Lanaro, A., Lednicky, R., Mariñas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., and Zrelov, P.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

The DIRAC experiment at CERN investigated in the reaction $\rm{p}(24~\rm{GeV}/c) + Ni$ the particle pairs $K^+K^-, \pi^+ \pi^-$ and $p \bar{p}$ with relative momentum $Q$ in the pair system less than 100 MeV/c. Because of background influence studies, DIRAC explored three subsamples of $K^+K^-$ pairs, obtained by subtracting -- using time-of-flight (TOF) technique -- background from initial $Q$ distributions with $K^+K^-$ sample fractions more than 70\%, 50\% and 30\%. The corresponding pair distributions in $Q$ and in its longitudinal projection $Q_L$ were analyzed first in a Coulomb model, which takes into account only Coulomb final state interaction (FSI) and assuming point-like pair production. This Coulomb model analysis leads to a $K^+K^-$ yield increase of about four at $Q_L=0.5$ MeV/c compared to 100 MeV/c. In order to study contributions from strong interaction, a second more sophisticated model was applied, considering besides Coulomb FSI also strong FSI via the resonances $f_0(980)$ and $a_0(980)$ and a variable distance $r^*$ between the produced $K$ mesons. This analysis was based on three different parameter sets for the pair production. For the 70\% subsample and with best parameters, $3680\pm 370$ $K^+K^-$ pairs was found to be compared to $3900\pm 410$ $K^+K^-$ extracted by means of the Coulomb model. Knowing the efficiency of the TOF cut for background suppression, the total number of detected $K^+K^-$ pairs was evaluated to be around $40000\pm 10\%$, which agrees with the result from the 30\% subsample. The $K^+K^-$ pair number in the 50\% subsample differs from the two other values by about three standard deviations, confirming -- as discussed in the paper -- that experimental data in this subsample is less reliable.

Published
2022
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4. Conceptual design of the Spin Physics Detector

Author

Abazov, V. M., Abramov, V., Afanasyev, L. G., Akhunzyanov, R. R., Akindinov, A. V., Akopov, N., Alekseev, I. G., Aleshko, A. M., Alexakhin, V. Yu., Alexeev, G. D., Alexeev, M., Amoroso, A., Anikin, I. V., Andreev, V. F., Anosov, V. A., Arbuzov, A. B., Azorskiy, N. I., Baldin, A. A., Balandina, V. V., Baldina, E. G., Barabanov, M. Yu., Barsov, S. G., Baskov, V. A., Beloborodov, A. N., Belov, I. N., Belova, A. P., Belyaev, A. V., Berdnikov, A. Ya., Berdnikov, Ya. A., Berezhnoy, A. V., Bleko, V. V., Bobkov, A. V., Bogoslovsky, D. N., Boguslavsky, I. N., Boltushkin, E. V., Boos, E. E., Burtsev, V. E., Chen, Lei, Chepurnov, A. S., Chiosso, M., Chumakov, A., Dalkarov, O. D., Datta, A., Demikhov, E. I., Denisenko, I. I., Denisov, O. Yu., Duginov, V. N., Dunin, V. B., Dygnarowicz, K., Efremov, A. V., El-Kholy, R., Eliseev, D. A., Enik, T. L., Fedin, O. L., Feofilov, G. A., Filatov, Yu. N., Finger, M., Frolov, V. N., Galinski, G., Galoyan, A. S., Trapaga, C. E Garsia, Gavrishchuk, O. P., Gerasimov, S. G., Glonti, L., Goloskokov, S. V., Golovanov, G. A., Golubev, A. A., M., Golubykh S., V., Goncharov P., O., Grafov N., Y., Gribkov D., Gribovsky, A. S., Gridin, A. O., Grinyov, B. V., Gritsay, K. I., Gromov, S. A., Gromov, V. A., Gurchin, Yu. V., Gusakov, Yu. V., Guskov, A. V., Guzman, F., Haidenbauer, J., Havranek, M., Ivanov, A. V., Ivanov, N. Ya., Isupov, A. Yu., Jary, V., Jia, Shi-Hai, Jokovic, D., Kaplii, A., Karpishkov, A. V., Kasianova, E. A., Kekelidze, G. D., Khabarov, S. V., Kharusov, P. R., Khrenov, A. N., Kim, V. T., Kirichkov, N. V., Kirin, D. Yu., Kishchin, I., Klekotko, A., Klopot, Ya., Kluev, A., Kokoulina, E. S., Komarov, V. I., Kondratenko, A. M., Kondratenko, M. A., Konorov, I., Kopylov, Yu. A., Korjik, M. V., Korovkin, P. S., Korzenev, A. Yu., Kostukov, E. V., Kotzinian, A., Kovalenko, A. D., Kovalenko, V. N., A., Kozhin M., Kramarenko, V. A., Kruglov, V. N., Kubankin, A., Kubankin, Yu., Kuleshov, S., Kovtun, V. E., Kulikov, A. V., Kurbatov, V. S., Kurjata, R., Kutuzov, S. A., Kuznetsova, E. V., Ladygin, E. A., Ladygin, V. P., Larionova, D. M., Lednicky, D., Lednicky, R., Li, Pei-Yu, Li, Xiao-Mei, Lobko, A. S., Luschevskaya, E., L'vov, A. I., Lyashchenko, V. N., Lysan, V. M., Lyubovitskij, V., Maggiora, A., Maleev, V. P., Maltsev, A., Malykhina, T. V., Makankin, A. M., Makarenko, V. V., Maletic, D., Malkevich, D. B., Marcisovsky, M., Martovitsky, E. V., Marzec, J., Merkin, M. M., Meshcheriakov, G. V., Mitrankov, Yu. M., Mitrankova, M. M., Mitrofanov, E. O., Morozov, B., Moshkovsky, I. V., Movsisyan, A., Nagorniy, S. N., Nechaeva, P. Yu., Nefedov, M. A., Nefedov, Yu. A., Negodaev, M. A., Neue, G., Nikiforov, D. N., Nikitin, V. A., Nikolaev, A. S., Oleynik, D. A., Ososkov, G. A., Panzieri, D., Parsamyan, B., Parzhitsky, S. S., Pastuszak, G., Pavlov, V. V., Pavlova, A. A., Pelevanyuk, I. S., Perepelkin, E. E., Peshekhonov, D. V., Petrosyan, A. Sh., Piskun, A. A., Plotnikov, V. V., Podgainy, D. V., Polozov, P., Polyakova, R. V., Polyansky, V. V., Popov, V. V., Popule, J., Prochazka, I., Prokhorov, I. K., Reva, S. N., Reznikov, S. G., Rezvaya, E. P., Richard, J. -M., Rogachevsky, O. V., Romanov, V. M., Rudenko, A. I., Rumyantsev, M. A., Rusinov, V., Rybakov, N. A., Rychter, A., Rymbekova, A., Safonov, A. B., Salamatin, K. M., Saleev, V. A., Samartsev, A. G., Savenkov, A. A., Savic, M., Semak, A. A., Shaikovsky, V. N., Shavrin, A. A., Sheremeteva, A. I., Shimanskii, S. S., Shipilova, A. V., Shtejer, K., Shulyakovsky, R., Sinitsa, A. A., Skachkov, N. B., Skachkova, A. N., Slunecka, M., Sluneckova, V., Solin, A. A., Solin, A. V., Song, Jin-Xin, Sotnikov, V. V., Sun, Peng-Fei, Starikova, S. Yu., Stavinskiy, A. V., Streletskaya, E. A., Strikman, M., Strusik-Kotlozh, D., Suchkov, S. I., Sultanov, R. I., Sun, Hao, Svirida, D. N., Tarasov, O. G., Tarkovskyi, E. I., Temerbayev, A., Terekhin, A. A., V., Tereschenko V., R., Terkulov A., V., Teryaev O., V., Tishevsky A., V., Tkachenko A., Tokmenin, A. A. V. V., Tomasek, L., Tomasi-Gustafsson, E., Topchiev, N. P., Topilin, N. D., Topko, B. L., Tosello, F., Trifonov, A., Troyan., Yu. A., Trunov, N. O., Tsenov, R., Usenko, E. A., Uzhinsky, V. V., Uzikov, Yu. N., Valiev, F. F., Vasilieva, E. V., Vechernin, V. V., Verkheev, A. Yu., Vertogradov, L. S., Vertogradova, Yu. L., Vesenkov, V. A., Virius, M., Volchansky, N. I., Volkov, I. S., Volkov, P. V., Vorobiev, A., Vrba, V., Wang, Qian, Yudin, I. P., Zamora, J., Zamyatin, N. I., Zaremba, K., Zelenov, A. V., Zemlyanichkina, E. V., Zhang, Yun-Yu, Zhang, Jun-Wei, Zhao, Ming-Rui, Zhao, Qiang, Zhi, Yu, Zhemchugov, A. S., Zhevlakov, A., Zhigareva, N. M., Zhmurin, P. N., Zhukov, I. A., Zhuravlev., N. I, Ziembicki, M., Zinin, A. V., Zubarev, E. V., and Zuev, M. I.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

The Spin Physics Detector, a universal facility for studying the nucleon spin structure and other spin-related phenomena with polarized proton and deuteron beams, is proposed to be placed in one of the two interaction points of the NICA collider that is under construction at the Joint Institute for Nuclear Research (Dubna, Russia). At the heart of the project there is huge experience with polarized beams at JINR. The main objective of the proposed experiment is the comprehensive study of the unpolarized and polarized gluon content of the nucleon. Spin measurements at the Spin Physics Detector at the NICA collider have bright perspectives to make a unique contribution and challenge our understanding of the spin structure of the nucleon. In this document the Conceptual Design of the Spin Physics Detector is presented.

Published
2021

5. COMET Phase-I Technical Design Report

Author

The COMET Collaboration, Abramishvili, R., Adamov, G., Akhmetshin, R. R., Allin, A., Angélique, J. C., Anishchik, V., Aoki, M., Aznabayev, D., Bagaturia, I., Ban, G., Ban, Y., Bauer, D., Baygarashev, D., Bondar, A. E., Cârloganu, C., Carniol, B., Chau, T. T., Chen, J. K., Chen, S. J., Cheung, Y. E., da Silva, W., Dauncey, P. D., Densham, C., Devidze, G., Dornan, P., Drutskoy, A., Duginov, V., Eguchi, Y., Epshteyn, L. B., Evtoukhovich, P., Fayer, S., Fedotovich, G. V., Finger Jr, M., Finger, M., Fujii, Y., Fukao, Y., Gabriel, J. L., Gay, P., Gillies, E., Grigoriev, D. N., Gritsay, K., Hai, V. H., Hamada, E., Hashim, I. H., Hashimoto, S., Hayashi, O., Hayashi, T., Hiasa, T., Ibrahim, Z. A., Igarashi, Y., Ignatov, F. V., Iio, M., Ishibashi, K., Issadykov, A., Itahashi, T., Jansen, A., Jiang, X. S., Jonsson, P., Kachelhoffer, T., Kalinnikov, V., Kaneva, E., Kapusta, F., Katayama, H., Kawagoe, K., Kawashima, R., Kazak, N., Kazanin, V. F., Kemularia, O., Khvedelidze, A., Koike, M., Kormoll, T., Kozlov, G. A., Kozyrev, A. N., Kravchenko, M., Krikler, B., Kumsiashvili, G., Kuno, Y., Kuriyama, Y., Kurochkin, Y., Kurup, A., Lagrange, B., Lai, J., Lee, M. J., Li, H. B., Litchfield, R. P., Li, W. G., Loan, T., Lomidze, D., Lomidze, I., Loveridge, P., Macharashvili, G., Makida, Y., Mao, Y. J., Markin, O., Matsuda, Y., Melkadze, A., Melnik, A., Mibe, T., Mihara, S., Miyamoto, N., Miyazaki, Y., Idris, F. Mohamad, Azmi, K. A. Mohamed Kamal, Moiseenko, A., Moritsu, M., Mori, Y., Motoishi, T., Nakai, H., Nakai, Y., Nakamoto, T., Nakamura, Y., Nakatsugawa, Y., Nakazawa, Y., Nash, J., Natori, H., Niess, V., Nioradze, M., Nishiguchi, H., Noguchi, K., Numao, T., O'Dell, J., Ogitsu, T., Ohta, S., Oishi, K., Okamoto, K., Okamura, T., Okinaka, K., Omori, C., Ota, T., Pasternak, J., Paulau, A., Picters, D., Ponariadov, V., Quémener, G., Ruban, A. A., Rusinov, V., Sabirov, B., Sakamoto, H., Sarin, P., Sasaki, K., Sato, A., Sato, J., Semertzidis, Y. K., Shigyo, N., Shoukavy, Dz., Slunecka, M., Stöckinger, D., Sugano, M., Tachimoto, T., Takayanagi, T., Tanaka, M., Tang, J., Tao, C. V., Teixeira, A. M., Tevzadze, Y., Thanh, T., Tojo, J., Tolmachev, S. S., Tomasek, M., Tomizawa, M., Toriashvili, T., Trang, H., Trekov, I., Tsamalaidze, Z., Tsverava, N., Uchida, T., Uchida, Y., Ueno, K., Velicheva, E., Volkov, A., Vrba, V., Abdullah, W. A. T. Wan, Warin-Charpentier, P., Wong, M. L., Wong, T. S., Wu, C., Xing, T. Y., Yamaguchi, H., Yamamoto, A., Yamanaka, M., Yamane, T., Yang, Y., Yano, T., Yao, W. C., Yeo, B., Yoshida, H., Yoshida, M., Yoshioka, T., Yuan, Y., Yudin, Yu. V., Zdorovets, M. V., Zhang, J., Zhang, Y., and Zuber, K.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of an aluminium nucleus ($\mu-e$ conversion, $\mu^- N \to e^- N$); a lepton flavor violating process. The experimental sensitivity goal for this process in the Phase-I experiment is $3.1\times10^{-15}$, or 90 % upper limit of branching ratio of $7\times 10^{-15}$, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the \mue conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described., Comment: A minor correction applied in Eq. 3

Published
2018
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6. First measurement of a long-lived $\pi^+ \pi^-$ atom lifetime

Author

Adeva, B., Afanasyev, L., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P. V., Doskarova, P., Drijard, D., Dudarev, A., Dumitriu, D., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Lamberto, A., Lanaro, A., Lednicky, R., Mariñas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Ovsiannikov, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G. F., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Trojek, T., Trusov, S., Vrba, T., Yazkov, V., Yoshimura, Y., and Zrelov, P.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like $\pi^+\pi^-$ atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96~mm and got broken up in the 2.1~\textmu{}m thick platinum foil. Analysing the observed number of atomic pairs, $n_A^L= \left.436^{+157}_{-61}\right|_\mathrm{tot}$, the lifetime of the 2$p$ state is found to be ${\tau_{2p}=(\left.0.45^{+1.08}_{-0.30}\right|_\mathrm{tot}) \cdot10^{-11}}$s, not contradicting the corresponding QED $2p$ state lifetime ${\tau_{2p}^\mathrm{QED}=1.17 \cdot 10^{-11}}$s. This lifetime value is three orders of magnitude larger than our previously measured value of the $\pi^+\pi^-$ atom ground state lifetime $\tau=(\left.3.15^{+0.28}_{-0.26}\right|_\mathrm{tot})\cdot 10^{-15}$s. Further studies of long-lived $\pi^+\pi^-$ atoms will allow to measure energy differences between $p$ and $s$ atomic states and so to determine $\pi\pi$ scattering lengths with the aim to check QCD predictions., Comment: 7 pages, 8 figures

Published
2018
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7. Measurement of the $\pi K$ atom lifetime and the $\pi K$ scattering length

Author

DIRAC Collaboration, Adeva, B., Afanasyev, L., Allkofer, Y., Amsler, C., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Drijard, D., Dudarev, A., Dumitriu, D., Federicova, P., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Kuptsov, A., Lamberto, A., Lanaro, A., Lednicky, R., Marinas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Tauscher, L., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

After having announced the statistically significant observation (5.6~$\sigma$) of the new exotic $\pi K$ atom, the DIRAC experiment at the CERN proton synchrotron presents the measurement of the corresponding atom lifetime, based on the full $\pi K$ data sample: $\tau = (5.5^{+5.0}_{-2.8}) \cdot 10^{-15}s$. By means of a precise relation ($<1\%$) between atom lifetime and scattering length, the following value for the S-wave isospin-odd $\pi K$ scattering length $a_0^{-}~=~\frac{1}{3}(a_{1/2}-a_{3/2})$ has been derived: $\left|a_0^-\right| = (0.072^{+0.031}_{-0.020}) M_{\pi}^{-1}$., Comment: 18 pages, 17 figures

Published
2017
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8. First $\pi K$ atom lifetime and $\pi K$ scattering length measurements

Author

Adeva, B., Afanasyev, L., Allkofer, Y., Amsler, C., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Ciocarlan, C., Constantinescu, S., Doskarova, P., Drijard, D., Dudarev, A., Duma, M., Dumitriu, D., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Kuptsov, A., Lamberto, A., Lanaro, A., Lednicky, R., Mariñas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Ponta, T., Prusa, P., Rappazzo, G., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Schacher, J., Sidorov, A., Smolik, J., Sugimoto, S., Takeutchi, F., Tauscher, L., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The results of a search for hydrogen-like atoms consisting of $\pi^{\mp}K^{\pm}$ mesons are presented. Evidence for $\pi K$ atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic $\pi K$ pairs from their breakup in the same target ($178 \pm 49$) and from Coulomb final state interaction ($653 \pm 42$). Using these results the analysis yields a first value for the $\pi K$ atom lifetime of $\tau=(2.5_{-1.8}^{+3.0})$ fs and a first model-independent measurement of the S-wave isospin-odd $\pi K$ scattering length $\left|a_0^-\right|=\frac{1}{3}\left|a_{1/2}-a_{3/2}\right|= \left(0.11_{-0.04}^{+0.09} \right)M_{\pi}^{-1}$ ($a_I$ for isospin $I$)., Comment: 14 pages, 8 figures

Published
2014
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9. Evidence for $\pi K$-atoms with DIRAC

Author

Adeva, B., Afanasyev, L., Allkofer, Y., Amsler, C., Anania, A., Benelli, A., Brekhovskikh, V., Caragheorgheopol, G., Cechak, T., Chiba, M., Chliapnikov, P., Ciocarlan, C., Constantinescu, S., Curceanu, C., Detraz, C., Dreossi, D., Drijard, D., Dudarev, A., Duma, M., Dumitriu, D., Fungueiriño, J. L., Gerndt, J., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iliescu, M., Karpukhin, V., Kluson, J., Kobayashi, M., Komarov, V., Kruglov, V., Kruglova, L., Kulikov, A., Kuptsov, A., Kurochkin, I., Lamberto, A., Lanaro, A., Lapshin, V., Lednicky, R., Sandri, P. Levi, Aguera, A. Lopez, Lucherini, V., Manuilov, I., Mariñas, C., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Pló, M., Rappazzo, G. F., Regenfus, C., Rochet, J., Romero, A., Ronjin, V., Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Sugimoto, S., Takeutchi, F., Tarasov, A., Tauscher, L., Trojek, T., Trusov, S., Utkin, V., Doce, O. Vázquez, Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Subjects
High Energy Physics - Experiment
Abstract

We present evidence for the first observation of electromagnetically bound $\pi^\pm K^\mp$-pairs ($\pi K$-atoms) with the DIRAC experiment at the CERN-PS. The $\pi K$-atoms are produced by the 24 GeV/c proton beam in a thin Pt-target and the $\pi^\pm$ and $K^\mp$-mesons from the atom dissociation are analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173 $\pm$ 54 $\pi K$-atoms. The mean life of $\pi K$-atoms is related to the s-wave $\pi K$-scattering lengths, the measurement of which is the goal of the experiment. From these first data we derive a lower limit for the mean life of 0.8 fs at 90% confidence level., Comment: 15 pages, 9 figures

Published
2009
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10. Upgraded DIRAC spectrometer at CERN PS for the investigation of ππ and πK atoms

Author

Adeva, B., Afanasyev, L., Allkofer, Y., Amsler, C., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Caragheorgheopol, Gh., Cechak, T., Chiba, M., Chliapnikov, P., Ciocarlan, C., Constantinescu, S., Detraz, C., Doskarova, P., Drijard, D., Dudarev, A., Duma, M., Dumitriu, D., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Kuptsov, A., Lamberto, A., Lanaro, A., Lednicky, R., Mariñas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G.F., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Tauscher, L., Trojek, T., Trusov, S., Ullaland, O., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Published
2016
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11. Investigation of <math><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math> pairs in the effective mass region near <math><mn>2</mn><msub><mi>m</mi><mi>K</mi></msub></math>

Author

Adeva, B., Afanasyev, L., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Drijard, D., Dudarev, A., Dumitriu, D., Federicova, P., Gorin, A., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglova, L., Kulikov, A., Kulish, E., Lamberto, A., Lanaro, A., Lednicky, R., Mari??as, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G., Romero Vidal, A., Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., and Zrelov, P.

Abstract

The DIRAC experiment at CERN investigated in the reaction p(24 GeV/c)+Ni the particle pairs K+K−,π+π−, and pp¯ with relative momentum Q in the pair system less than 100 MeV/c. Because of background influence studies, DIRAC explored three subsamples of K+K− pairs, obtained by subtracting-using the time-of-flight (TOF) technique-the background from initial Q distributions with K+K− sample fractions more than 70%, 50%, and 30%. The corresponding pair distributions in Q and in its longitudinal projection QL were analyzed first in a Coulomb model, which takes into account only the Coulomb final-state interaction (FSI) and assuming pointlike pair production. This Coulomb model analysis leads to a K+K− yield increase of about four at QL=0.5 MeV/c compared to 100 MeV/c. In order to study contributions from strong interaction, a second more sophisticated model was applied, considering also strong FSI via the resonances f0(980) and a0(980) and a variable distance r* between the produced K mesons besides Coulomb FSI. This analysis was based on three different parameter sets for the pair production. For the 70% subsample and with the best parameters, 3680±370 K+K− pairs were found to be compared to 3900±410 K+K− extracted by means of the Coulomb model. Knowing the efficiency of the TOF cut for background suppression, the total number of detected K+K− pairs was evaluated to be around 40000±10%, which agrees with the result from the 30% subsample. The K+K− pair number in the 50% subsample differs from the two other values by about three standard deviations, confirming—as discussed in the paper—that experimental data in this subsample is less reliable. In summary, the upgraded DIRAC experiment observed increased K+K− production at small relative momentum Q. The pair distribution in Q is well described by Coulomb FSI, whereas a potential influence from strong interaction in this Q region is insignificant within experimental errors.

Published
2022

13. First Measurement of a Long-Lived π^{+}π^{-} Atom Lifetime

Author

Adeva, B., Afanasyev, L., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P. V., Doskarova, P., Drijard, D., Dudarev, A., Dumitriu, D., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Lamberto, A., Lanaro, A., Lednicky, R., Mariñas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Ovsiannikov, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G. F., Romero Vidal, A., Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., and Zrelov, P.

Abstract

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike π+π− atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm between the target and a 2.1 μm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, nAL=436−61+157|tot, the lifetime of the 2p state is found to be τ2p=(0.45−0.30+1.08|tot)×10−11 s, not contradicting the corresponding QED 2p state lifetime τ2pQED=1.17×10−11 s. This lifetime value is three orders of magnitude larger than our previously measured value of the π+π− atom ground state lifetime τ=(3.15−0.26+0.28|tot)×10−15 s. Further studies of long-lived π+π− atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor ππ scattering lengths with the aim to check QCD predictions.

Published
2018

14. First measurement of a long-lived $��^+ ��^-$ atom lifetime

Author

Adeva, B., Afanasyev, L., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P. V., Doskarova, P., Drijard, D., Dudarev, A., Dumitriu, D., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Lamberto, A., Lanaro, A., Lednicky, R., Mari��as, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Ovsiannikov, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G. F., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Trojek, T., Trusov, S., Vrba, T., Yazkov, V., Yoshimura, Y., and Zrelov, P.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, Physics::Atomic Physics, Nuclear Experiment (nucl-ex)
Abstract

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like $��^+��^-$ atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96~mm and got broken up in the 2.1~\textmu{}m thick platinum foil. Analysing the observed number of atomic pairs, $n_A^L= \left.436^{+157}_{-61}\right|_\mathrm{tot}$, the lifetime of the 2$p$ state is found to be ${��_{2p}=(\left.0.45^{+1.08}_{-0.30}\right|_\mathrm{tot}) \cdot10^{-11}}$s, not contradicting the corresponding QED $2p$ state lifetime ${��_{2p}^\mathrm{QED}=1.17 \cdot 10^{-11}}$s. This lifetime value is three orders of magnitude larger than our previously measured value of the $��^+��^-$ atom ground state lifetime $��=(\left.3.15^{+0.28}_{-0.26}\right|_\mathrm{tot})\cdot 10^{-15}$s. Further studies of long-lived $��^+��^-$ atoms will allow to measure energy differences between $p$ and $s$ atomic states and so to determine $����$ scattering lengths with the aim to check QCD predictions., 7 pages, 8 figures

Published
2018
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15. First Measurement of a Long-Lived π+π− Atom Lifetime

Author

Adeva, B., primary, Afanasyev, L., additional, Anania, A., additional, Aogaki, S., additional, Benelli, A., additional, Brekhovskikh, V., additional, Cechak, T., additional, Chiba, M., additional, Chliapnikov, P. V., additional, Doskarova, P., additional, Drijard, D., additional, Dudarev, A., additional, Dumitriu, D., additional, Fluerasu, D., additional, Gorin, A., additional, Gorchakov, O., additional, Gritsay, K., additional, Guaraldo, C., additional, Gugiu, M., additional, Hansroul, M., additional, Hons, Z., additional, Horikawa, S., additional, Iwashita, Y., additional, Karpukhin, V., additional, Kluson, J., additional, Kobayashi, M., additional, Kruglov, V., additional, Kruglova, L., additional, Kulikov, A., additional, Kulish, E., additional, Lamberto, A., additional, Lanaro, A., additional, Lednicky, R., additional, Mariñas, C., additional, Martincik, J., additional, Nemenov, L., additional, Nikitin, M., additional, Okada, K., additional, Olchevskii, V., additional, Ovsiannikov, V., additional, Pentia, M., additional, Penzo, A., additional, Plo, M., additional, Prusa, P., additional, Rappazzo, G. F., additional, Romero Vidal, A., additional, Ryazantsev, A., additional, Rykalin, V., additional, Saborido, J., additional, Schacher, J., additional, Sidorov, A., additional, Smolik, J., additional, Takeutchi, F., additional, Trojek, T., additional, Trusov, S., additional, Urban, T., additional, Vrba, T., additional, Yazkov, V., additional, Yoshimura, Y., additional, and Zrelov, P., additional

Published
2019
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16. Measurement of the $��K$ atom lifetime and the $��K$ scattering length

Author

DIRAC Collaboration, Adeva, B., Afanasyev, L., Allkofer, Y., Amsler, C., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Drijard, D., Dudarev, A., Dumitriu, D., Federicova, P., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Kuptsov, A., Lamberto, A., Lanaro, A., Lednicky, R., Marinas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Tauscher, L., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract

After having announced the statistically significant observation (5.6~$��$) of the new exotic $��K$ atom, the DIRAC experiment at the CERN proton synchrotron presents the measurement of the corresponding atom lifetime, based on the full $��K$ data sample: $��= (5.5^{+5.0}_{-2.8}) \cdot 10^{-15}s$. By means of a precise relation ($, 18 pages, 17 figures

Published
2017
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17. First observation of long-lived π+π− atoms

Author

Adeva, B., Afanasyev, L., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Doskarova, P., Drijard, D., Dudarev, A., Duma, M., Dumitriu, D., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Kuptsov, A., Lamberto, A., Lanaro, A., Lednicky, R., Mariñas, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Ovsiannikov, V., Pentia, M., Penzo, A., Plo, M., Prusa, P., Rappazzo, G., Romero Vidal, A., Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Takeutchi, F., Tauscher, L., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Published
2015
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18. First $��K$ atom lifetime and $��K$ scattering length measurements

Author

Adeva, B., Afanasyev, L., Allkofer, Y., Amsler, C., Anania, A., Aogaki, S., Benelli, A., Brekhovskikh, V., Cechak, T., Chiba, M., Chliapnikov, P., Ciocarlan, C., Constantinescu, S., Doskarova, P., Drijard, D., Dudarev, A., Duma, M., Dumitriu, D., Fluerasu, D., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iwashita, Y., Karpukhin, V., Kluson, J., Kobayashi, M., Kruglov, V., Kruglova, L., Kulikov, A., Kulish, E., Kuptsov, A., Lamberto, A., Lanaro, A., Lednicky, R., Mari��as, C., Martincik, J., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Plo, M., Ponta, T., Prusa, P., Rappazzo, G., Vidal, A. Romero, Ryazantsev, A., Rykalin, V., Schacher, J., Sidorov, A., Smolik, J., Sugimoto, S., Takeutchi, F., Tauscher, L., Trojek, T., Trusov, S., Urban, T., Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract

The results of a search for hydrogen-like atoms consisting of $��^{\mp}K^{\pm}$ mesons are presented. Evidence for $��K$ atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic $��K$ pairs from their breakup in the same target ($178 \pm 49$) and from Coulomb final state interaction ($653 \pm 42$). Using these results the analysis yields a first value for the $��K$ atom lifetime of $��=(2.5_{-1.8}^{+3.0})$ fs and a first model-independent measurement of the S-wave isospin-odd $��K$ scattering length $\left|a_0^-\right|=\frac{1}{3}\left|a_{1/2}-a_{3/2}\right|= \left(0.11_{-0.04}^{+0.09} \right)M_��^{-1}$ ($a_I$ for isospin $I$)., 14 pages, 8 figures

Published
2014
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19. Search for Long-Lived States of $\pi^+\pi^-$ Atoms : Addendum to the DIRAC Proposal

Author

Adeva, B, Afanasyev, L, Anania, A, Aogaki, S, Augsten, K, Batyuk, P, Benelli, A, Brekhovskikh, V, Cechak, T, Chiba, M, Ciortea, C, Curceanu, C, Doskarova, P, Dudarev, A, Dumitriu, D, Drijard, D, Fluerasu, D, Gortchakov, O, Gritsay, K, Guaraldo, C, Gugiu, M, Hansroul, M, Hosek, R, Hons, Z, Iwashita, Y, Karpukhin, V, Kluson, J, Kobayashi, M, Kruglov, V, Kruglova, L, Kulikov, A, Kulish, E, Kuptsov, A, Lamberto, A, Lednicky, R, Martincik, J, Nemenov, L, Nikitin, M, Okada, K, Pentia, M, Plo, M, Prusa, P, Rappazzo, G, Ryazantsev, A, Romero, A, Ronzhin, V, Rykalin, V, Saborido, J, Schacher, J, Shlyapnikov, P, Smolik, J, Takeutchi, F, Trojek, T, Urban, T, Vrba, T, Vazquez, P, Yazkov, V, Yoshimura, Y, Zhabitsky, M, and Zrelov, P

Subjects
Detectors and Experimental Techniques
Abstract

The proposed experiment is a further development of the DIRAC experiment already running at CERN PS. The observation of long-lived (metastable) states of $\pi^+\pi^-$ atoms ($A_{2\pi}$) will be performed with the same setup. This observation opens a possibility to measure the energy difference between $ns$ and $np$ states and to determine the value of the combination $2a_0+a_2$ of S-wave $\pi\pi$ scattering lengths in a model-independent way. In combination with the $A_{2\pi}$ lifetime measurement providing the value $|a_0-a_2|$ DIRAC is in the position to get $a_0$ and $a_2$ separately on the basis of $A_{2\pi}$ data only.

Published
2012

20. Search for Long-Lived States of $\pi^+\pi^-$ Atoms: Addendum to the DIRAC Proposal

Author

Adeva, B, Afanasyev, L, Amsler, C, Anania, A, Aogaki, S, Augsten, K, Benelli, A, Brekhovskikh, V, Cechak, T, Chiba, M, Ciortea, C, Ciocarlan, C, Constantinescu, S, Curceanu, C, Doskarova, P, Dudarev, A, Dumitriu, D, Drijard, D, Enulescu, A, Fluerasu, D, Gortchakov, O, Gritsay, K, Guaraldo, C, Gugiu, M, Hansroul, M, Hosek, R, Hons, Z, Karpukhin, V, Kluson, J, Kobayashi, M, Kulikov, A, Kulish, E, Kuptsov, A, Kruglov, V, Kruglova, L, Kuroda, K, Lamberto, A, Lednicky, R, Martincik, J, Nemenov, L, Nikitin, M, Okada, K, Pentia, M, Plo, M, Prusa, P, Rappazzo, G, Ryazantsev, A, Romero, A, Ronzhin, V, Rykalin, V, Saborido, J, Schacher, J, Shlyapnikov, P, Smolik, J, Takeutchi, F, Tarasov, A, Trojek, T, Urban, T, Vrba, T, Vazquez, P, Yazkov, V, Yoshimura, Y, Zhabitsky, M, and Zrelov, P

Subjects
Detectors and Experimental Techniques
Abstract

The proposed experiment is a further development of the DIRAC experiment already running at CERN PS. Up to now more than 21000 $\pi^+\pi^-$ pairs originated from the $\pi^+\pi^-$ atom ($A_{2\pi}$) breakup were identified and the overall accuracy of the $A_{2\pi}$ lifetime is about 9% in accordance with the DIRAC proposal. This measurement allowed to extract the difference $|a_0-a_2|$ of $s$-wave $\pi\pi$-scattering length with accuracy of 4.3%. The observation of long-lived (metastable) $A_{2\pi}$ states will be performed with the same setup. This observation opens a possibility to measure the energy difference between $ns$ and $np$ states and to determine the value of another combination $2a_0+a_2$ of $\pi\pi$ scattering length in a model-independent way. In combination with the first measurement it allows to get $a_0$ and $a_2$ separately. An additional measurement of the multiple scattering angles in different materials with accuracy better than 1% will be performed in parallel with the observation. This measurement is needed to improve the systematic accuracy in the $A_{2\pi}$ lifetime for the data already collected in 2008--2010.

Published
2011

21. Evidence for $��K$-atoms with DIRAC

Author

Adeva, B., Afanasyev, L., Allkofer, Y., Amsler, C., Anania, A., Benelli, A., Brekhovskikh, V., Caragheorgheopol, G., Cechak, T., Chiba, M., Chliapnikov, P., Ciocarlan, C., Constantinescu, S., Curceanu, C., Detraz, C., Dreossi, D., Drijard, D., Dudarev, A., Duma, M., Dumitriu, D., Fungueiri��o, J. L., Gerndt, J., Gorin, A., Gorchakov, O., Gritsay, K., Guaraldo, C., Gugiu, M., Hansroul, M., Hons, Z., Horikawa, S., Iliescu, M., Karpukhin, V., Kluson, J., Kobayashi, M., Komarov, V., Kruglov, V., Kruglova, L., Kulikov, A., Kuptsov, A., Kurochkin, I., Lamberto, A., Lanaro, A., Lapshin, V., Lednicky, R., Sandri, P. Levi, Aguera, A. Lopez, Lucherini, V., Manuilov, I., Mari��as, C., Nemenov, L., Nikitin, M., Okada, K., Olchevskii, V., Pentia, M., Penzo, A., Pl��, M., Rappazzo, G. F., Regenfus, C., Rochet, J., Romero, A., Ronjin, V., Ryazantsev, A., Rykalin, V., Saborido, J., Schacher, J., Sidorov, A., Smolik, J., Sugimoto, S., Takeutchi, F., Tarasov, A., Tauscher, L., Trojek, T., Trusov, S., Utkin, V., Doce, O. V��zquez, Vrba, T., Yazkov, V., Yoshimura, Y., Zhabitsky, M., and Zrelov, P.

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences
Abstract

We present evidence for the first observation of electromagnetically bound $��^\pm K^\mp$-pairs ($��K$-atoms) with the DIRAC experiment at the CERN-PS. The $��K$-atoms are produced by the 24 GeV/c proton beam in a thin Pt-target and the $��^\pm$ and $K^\mp$-mesons from the atom dissociation are analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173 $\pm$ 54 $��K$-atoms. The mean life of $��K$-atoms is related to the s-wave $��K$-scattering lengths, the measurement of which is the goal of the experiment. From these first data we derive a lower limit for the mean life of 0.8 fs at 90% confidence level., 15 pages, 9 figures

Published
2009
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22. First πK atom lifetime and πK scattering length measurements

Author

Adeva, B., primary, Afanasyev, L., additional, Allkofer, Y., additional, Amsler, C., additional, Anania, A., additional, Aogaki, S., additional, Benelli, A., additional, Brekhovskikh, V., additional, Cechak, T., additional, Chiba, M., additional, Chliapnikov, P., additional, Ciocarlan, C., additional, Constantinescu, S., additional, Doskarova, P., additional, Drijard, D., additional, Dudarev, A., additional, Duma, M., additional, Dumitriu, D., additional, Fluerasu, D., additional, Gorin, A., additional, Gorchakov, O., additional, Gritsay, K., additional, Guaraldo, C., additional, Gugiu, M., additional, Hansroul, M., additional, Hons, Z., additional, Horikawa, S., additional, Iwashita, Y., additional, Karpukhin, V., additional, Kluson, J., additional, Kobayashi, M., additional, Kruglov, V., additional, Kruglova, L., additional, Kulikov, A., additional, Kulish, E., additional, Kuptsov, A., additional, Lamberto, A., additional, Lanaro, A., additional, Lednicky, R., additional, Mariñas, C., additional, Martincik, J., additional, Nemenov, L., additional, Nikitin, M., additional, Okada, K., additional, Olchevskii, V., additional, Pentia, M., additional, Penzo, A., additional, Plo, M., additional, Ponta, T., additional, Prusa, P., additional, Rappazzo, G., additional, Romero Vidal, A., additional, Ryazantsev, A., additional, Rykalin, V., additional, Saborido, J., additional, Schacher, J., additional, Sidorov, A., additional, Smolik, J., additional, Sugimoto, S., additional, Takeutchi, F., additional, Tauscher, L., additional, Trojek, T., additional, Trusov, S., additional, Urban, T., additional, Vrba, T., additional, Yazkov, V., additional, Yoshimura, Y., additional, Zhabitsky, M., additional, and Zrelov, P., additional

Published
2014
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23. Lifetime Measurements of $ \pi ^+ \pi ^- $ and $\pi^{+-} K^{-+}$ Atoms to Test Low-Energy QCD Predictions

Author

Rykalin, V, Dumitriu, D E, Afanasyev, L, Nemenov, L, Gritsay, K, Ryazantsev, A, Detraz, C C, Okada, K, Brekhovskikh, V, Smolik, J, Pentia, M C, Kruglova, L, Zhabitskiy, M, Kluson, J, Chiba, M, Dreossi, D, Kulikov, A, Benelli, A, Takeutchi, F, and Nikitin, M

Subjects
Nuclear Experiment
Abstract

%PS212 \\ \\ The proposed experiment aims to measure the lifetime of $ \pi ^+ \pi ^- $ atoms in the ground state with 10\% precision, using the 24~GeV/c proton beam of the CERN Proton Synchrotron. As the value of the above lifetime of order 10$ ^- ^{1} ^{5} $s is dictated by a strong interaction at low energy, the precise measurement of this quantity enables to determine a combination of S-wave pion scattering lengths to 5\%. Pion scattering lengths have been calculated in the framework of chiral perturbation theory and values predicted at the same level of accuracy have, up to now, never been confronted with accurate experimental data. Such a measurement would submit the understanding of chiral symmetry breaking of QCD to a crucial test.

Published
2002

24. Evidence for πK-atoms with DIRAC

Author

Adeva, B., primary, Afanasyev, L., additional, Allkofer, Y., additional, Amsler, C., additional, Anania, A., additional, Benelli, A., additional, Brekhovskikh, V., additional, Caragheorgheopol, G., additional, Cechak, T., additional, Chiba, M., additional, Chliapnikov, P., additional, Ciocarlan, C., additional, Constantinescu, S., additional, Curceanu, C., additional, Detraz, C., additional, Dreossi, D., additional, Drijard, D., additional, Dudarev, A., additional, Duma, M., additional, Dumitriu, D., additional, Fungueiriño, J.L., additional, Gerndt, J., additional, Gorin, A., additional, Gorchakov, O., additional, Gritsay, K., additional, Guaraldo, C., additional, Gugiu, M., additional, Hansroul, M., additional, Hons, Z., additional, Horikawa, S., additional, Iliescu, M., additional, Karpukhin, V., additional, Kluson, J., additional, Kobayashi, M., additional, Komarov, V., additional, Kruglov, V., additional, Kruglova, L., additional, Kulikov, A., additional, Kuptsov, A., additional, Kurochkin, I., additional, Lamberto, A., additional, Lanaro, A., additional, Lapshin, V., additional, Lednicky, R., additional, Levi Sandri, P., additional, Lopez Aguera, A., additional, Lucherini, V., additional, Manuilov, I., additional, Mariñas, C., additional, Nemenov, L., additional, Nikitin, M., additional, Okada, K., additional, Olchevskii, V., additional, Pentia, M., additional, Penzo, A., additional, Pló, M., additional, Rappazzo, G.F., additional, Regenfus, C., additional, Rochet, J., additional, Romero, A., additional, Ronjin, V., additional, Ryazantsev, A., additional, Rykalin, V., additional, Saborido, J., additional, Schacher, J., additional, Sidorov, A., additional, Smolik, J., additional, Sugimoto, S., additional, Takeutchi, F., additional, Tarasov, A., additional, Tauscher, L., additional, Trojek, T., additional, Trusov, S., additional, Utkin, V., additional, Vázquez Doce, O., additional, Vrba, T., additional, Yazkov, V., additional, Yoshimura, Y., additional, Zhabitsky, M., additional, and Zrelov, P., additional

Published
2009
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26. Observation of π^{-}K^{+} and π^{+}K^{-} Atoms.

Author

Adeva B, Afanasyev L, Allkofer Y, Amsler C, Anania A, Aogaki S, Benelli A, Brekhovskikh V, Cechak T, Chiba M, Chliapnikov P, Doskarova P, Drijard D, Dudarev A, Dumitriu D, Fluerasu D, Gorin A, Gorchakov O, Gritsay K, Guaraldo C, Gugiu M, Hansroul M, Hons Z, Horikawa S, Iwashita Y, Karpukhin V, Kluson J, Kobayashi M, Kruglov V, Kruglova L, Kulikov A, Kulish E, Kuptsov A, Lamberto A, Lanaro A, Lednicky R, Mariñas C, Martincik J, Nemenov L, Nikitin M, Okada K, Olchevskii V, Pentia M, Penzo A, Plo M, Prusa P, Rappazzo G, Romero Vidal A, Ryazantsev A, Rykalin V, Saborido J, Schacher J, Sidorov A, Smolik J, Takeutchi F, Tauscher L, Trojek T, Trusov S, Urban T, Vrba T, Yazkov V, Yoshimura Y, Zhabitsky M, and Zrelov P

Abstract

The observation of hydrogenlike πK atoms, consisting of π^{-}K^{+} or π^{+}K^{-} mesons, is presented. The atoms are produced by 24  GeV/c protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. The breakup (ionization) of πK atoms in the same targets yields characteristic πK pairs, called "atomic pairs," with small relative momenta Q in the pair center-of-mass system. The upgraded DIRAC experiment observed 349±62 such atomic πK pairs, corresponding to a signal of 5.6 standard deviations. This is the first statistically significant observation of the strange dimesonic πK atom.

Published
2016
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