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M. Jacewicz
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M. Jacewicz
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editors
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Cagayan de Oro
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Philippines

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High Energy Physics - Experiment (23)
 
Nuclear Experiment (18)
 
High Energy Physics - Phenomenology (4)
 
Physics - Accelerator Physics (2)
 
Physics - Instrumentation and Detectors (2)
 
Nuclear Theory (1)
 
Quantum Physics (1)

Publications Authored By M. Jacewicz

2016Aug
Authors: The CLIC, CLICdp collaborations, :, M. J. Boland, U. Felzmann, P. J. Giansiracusa, T. G. Lucas, R. P. Rassool, C. Balazs, T. K. Charles, K. Afanaciev, I. Emeliantchik, A. Ignatenko, V. Makarenko, N. Shumeiko, A. Patapenka, I. Zhuk, A. C. Abusleme Hoffman, M. A. Diaz Gutierrez, M. Vogel Gonzalez, Y. Chi, X. He, G. Pei, S. Pei, G. Shu, X. Wang, J. Zhang, F. Zhao, Z. Zhou, H. Chen, Y. Gao, W. Huang, Y. P. Kuang, B. Li, Y. Li, J. Shao, J. Shi, C. Tang, X. Wu, L. Ma, Y. Han, W. Fang, Q. Gu, D. Huang, X. Huang, J. Tan, Z. Wang, Z. Zhao, T. Laštovička, U. Uggerhoj, T. N. Wistisen, A. Aabloo, K. Eimre, K. Kuppart, S. Vigonski, V. Zadin, M. Aicheler, E. Baibuz, E. Brücken, F. Djurabekova, P. Eerola, F. Garcia, E. Haeggström, K. Huitu, V. Jansson, V. Karimaki, I. Kassamakov, A. Kyritsakis, S. Lehti, A. Meriläinen, R. Montonen, T. Niinikoski, K. Nordlund, K. Österberg, M. Parekh, N. A. Törnqvist, J. Väinölä, M. Veske, W. Farabolini, A. Mollard, O. Napoly, F. Peauger, J. Plouin, P. Bambade, I. Chaikovska, R. Chehab, M. Davier, W. Kaabi, E. Kou, F. LeDiberder, R. Pöschl, D. Zerwas, B. Aimard, G. Balik, J. -P. Baud, J. -J. Blaising, L. Brunetti, M. Chefdeville, C. Drancourt, N. Geoffroy, J. Jacquemier, A. Jeremie, Y. Karyotakis, J. M. Nappa, S. Vilalte, G. Vouters, A. Bernard, I. Peric, M. Gabriel, F. Simon, M. Szalay, N. van der Kolk, T. Alexopoulos, E. N. Gazis, N. Gazis, E. Ikarios, V. Kostopoulos, S. Kourkoulis, P. D. Gupta, P. Shrivastava, H. Arfaei, M. K. Dayyani, H. Ghasem, S. S. Hajari, H. Shaker, Y. Ashkenazy, H. Abramowicz, Y. Benhammou, O. Borysov, S. Kananov, A. Levy, I. Levy, O. Rosenblat, G. D'Auria, S. Di Mitri, T. Abe, A. Aryshev, T. Higo, Y. Makida, S. Matsumoto, T. Shidara, T. Takatomi, Y. Takubo, T. Tauchi, N. Toge, K. Ueno, J. Urakawa, A. Yamamoto, M. Yamanaka, R. Raboanary, R. Hart, H. van der Graaf, G. Eigen, J. Zalieckas, E. Adli, R. Lillestøl, L. Malina, J. Pfingstner, K. N. Sjobak, W. Ahmed, M. I. Asghar, H. Hoorani, S. Bugiel, R. Dasgupta, M. Firlej, T. A. Fiutowski, M. Idzik, M. Kopec, M. Kuczynska, J. Moron, K. P. Swientek, W. Daniluk, B. Krupa, M. Kucharczyk, T. Lesiak, A. Moszczynski, B. Pawlik, P. Sopicki, T. Wojtoń, L. Zawiejski, J. Kalinowski, M. Krawczyk, A. F. Żarnecki, E. Firu, V. Ghenescu, A. T. Neagu, T. Preda, I-S. Zgura, A. Aloev, N. Azaryan, J. Budagov, M. Chizhov, M. Filippova, V. Glagolev, A. Gongadze, S. Grigoryan, D. Gudkov, V. Karjavine, M. Lyablin, A. Olyunin, A. Samochkine, A. Sapronov, G. Shirkov, V. Soldatov, A. Solodko, E. Solodko, G. Trubnikov, I. Tyapkin, V. Uzhinsky, A. Vorozhtov, E. Levichev, N. Mezentsev, P. Piminov, D. Shatilov, P. Vobly, K. Zolotarev, I. Bozovic Jelisavcic, G. Kacarevic, S. Lukic, G. Milutinovic-Dumbelovic, M. Pandurovic, U. Iriso, F. Perez, M. Pont, J. Trenado, M. Aguilar-Benitez, J. Calero, L. Garcia-Tabares, D. Gavela, J. L. Gutierrez, D. Lopez, F. Toral, D. Moya, A. Ruiz Jimeno, I. Vila, T. Argyropoulos, C. Blanch Gutierrez, M. Boronat, D. Esperante, A. Faus-Golfe, J. Fuster, N. Fuster Martinez, N. Galindo Muñoz, I. García, J. Giner Navarro, E. Ros, M. Vos, R. Brenner, T. Ekelöf, M. Jacewicz, J. Ögren, M. Olvegård, R. Ruber, V. Ziemann, D. Aguglia, N. Alipour Tehrani, A. Andersson, F. Andrianala, F. Antoniou, K. Artoos, S. Atieh, R. Ballabriga Sune, M. J. Barnes, J. Barranco Garcia, H. Bartosik, C. Belver-Aguilar, A. Benot Morell, D. R. Bett, S. Bettoni, G. Blanchot, O. Blanco Garcia, X. A. Bonnin, O. Brunner, H. Burkhardt, S. Calatroni, M. Campbell, N. Catalan Lasheras, M. Cerqueira Bastos, A. Cherif, E. Chevallay, B. Constance, R. Corsini, B. Cure, S. Curt, B. Dalena, D. Dannheim, G. De Michele, L. De Oliveira, N. Deelen, J. P. Delahaye, T. Dobers, S. Doebert, M. Draper, F. Duarte Ramos, A. Dubrovskiy, K. Elsener, J. Esberg, M. Esposito, V. Fedosseev, P. Ferracin, A. Fiergolski, K. Foraz, A. Fowler, F. Friebel, J-F. Fuchs, C. A. Fuentes Rojas, A. Gaddi, L. Garcia Fajardo, H. Garcia Morales, C. Garion, L. Gatignon, J-C. Gayde, H. Gerwig, A. N. Goldblatt, C. Grefe, A. Grudiev, F. G. Guillot-Vignot, M. L. Gutt-Mostowy, M. Hauschild, C. Hessler, J. K. Holma, E. Holzer, M. Hourican, D. Hynds, Y. Inntjore Levinsen, B. Jeanneret, E. Jensen, M. Jonker, M. Kastriotou, J. M. K. Kemppinen, R. B. Kieffer, W. Klempt, O. Kononenko, A. Korsback, E. Koukovini Platia, J. W. Kovermann, C-I. Kozsar, I. Kremastiotis, S. Kulis, A. Latina, F. Leaux, P. Lebrun, T. Lefevre, L. Linssen, X. Llopart Cudie, A. A. Maier, H. Mainaud Durand, E. Manosperti, C. Marelli, E. Marin Lacoma, R. Martin, S. Mazzoni, G. Mcmonagle, O. Mete, L. M. Mether, M. Modena, R. M. Münker, T. Muranaka, E. Nebot Del Busto, N. Nikiforou, D. Nisbet, J-M. Nonglaton, F. X. Nuiry, A. Nürnberg, M. Olvegard, J. Osborne, S. Papadopoulou, Y. Papaphilippou, A. Passarelli, M. Patecki, L. Pazdera, D. Pellegrini, K. Pepitone, E. Perez Codina, A. Perez Fontenla, T. H. B. Persson, M. Petrič, F. Pitters, S. Pittet, F. Plassard, R. Rajamak, S. Redford, Y. Renier, S. F. Rey, G. Riddone, L. Rinolfi, E. Rodriguez Castro, P. Roloff, C. Rossi, V. Rude, G. Rumolo, A. Sailer, E. Santin, D. Schlatter, H. Schmickler, D. Schulte, N. Shipman, E. Sicking, R. Simoniello, P. K. Skowronski, P. Sobrino Mompean, L. Soby, M. P. Sosin, S. Sroka, S. Stapnes, G. Sterbini, R. Ström, I. Syratchev, F. Tecker, P. A. Thonet, L. Timeo, H. Timko, R. Tomas Garcia, P. Valerio, A. L. Vamvakas, A. Vivoli, M. A. Weber, R. Wegner, M. Wendt, B. Woolley, W. Wuensch, J. Uythoven, H. Zha, P. Zisopoulos, M. Benoit, M. Vicente Barreto Pinto, M. Bopp, H. H. Braun, M. Csatari Divall, M. Dehler, T. Garvey, J. Y. Raguin, L. Rivkin, R. Zennaro, A. Aksoy, Z. Nergiz, E. Pilicer, I. Tapan, O. Yavas, V. Baturin, R. Kholodov, S. Lebedynskyi, V. Miroshnichenko, S. Mordyk, I. Profatilova, V. Storizhko, N. Watson, A. Winter, J. Goldstein, S. Green, J. S. Marshall, M. A. Thomson, B. Xu, W. A. Gillespie, R. Pan, M. A Tyrk, D. Protopopescu, A. Robson, R. Apsimon, I. Bailey, G. Burt, D. Constable, A. Dexter, S. Karimian, C. Lingwood, M. D. Buckland, G. Casse, J. Vossebeld, A. Bosco, P. Karataev, K. Kruchinin, K. Lekomtsev, L. Nevay, J. Snuverink, E. Yamakawa, V. Boisvert, S. Boogert, G. Boorman, S. Gibson, A. Lyapin, W. Shields, P. Teixeira-Dias, S. West, R. Jones, N. Joshi, R. Bodenstein, P. N. Burrows, G. B. Christian, D. Gamba, C. Perry, J. Roberts, J. A. Clarke, N. A. Collomb, S. P. Jamison, B. J. A. Shepherd, D. Walsh, M. Demarteau, J. Repond, H. Weerts, L. Xia, J. D. Wells, C. Adolphsen, T. Barklow, M. Breidenbach, N. Graf, J. Hewett, T. Markiewicz, D. McCormick, K. Moffeit, Y. Nosochkov, M. Oriunno, N. Phinney, T. Rizzo, S. Tantawi, F. Wang, J. Wang, G. White, M. Woodley

The Compact Linear Collider (CLIC) is a multi-TeV high-luminosity linear e+e- collider under development. For an optimal exploitation of its physics potential, CLIC is foreseen to be built and operated in a staged approach with three centre-of-mass energy stages ranging from a few hundred GeV up to 3 TeV. The first stage will focus on precision Standard Model physics, in particular Higgs and top-quark measurements. Read More

One of the basic motivations of the KLOE and KLOE-2 collaborations is the test of fundamental symmetries and the search for phenomena beyond the Standard Model via the hadronic and leptonic decays of ground-state mesons and via their production in the fusion of virtual gamma quanta exchanged between colliding electrons and positrons. This contribution includes brief description of results of recent analysis of the KLOE data aimed at (i) the search for the dark matter boson, (ii) determination of the hadronic and light-by-light contributions to the g-2 muon anomaly and (iii) tests of QCD anomalies. Read More

Understanding the effects of RF breakdown in high-gradient accelerator structures on the accelerated beam is an extremely relevant aspect in the development of the Compact Linear Collider (CLIC) and is one of the main issues addressed at the Two-beam Test Stand at the CLIC Test Facility 3 at CERN. During a RF breakdown large electro-magnetic fields are generated and produce parasitic magnetic fields which interact with the accelerated beam affecting its orbit and energy. We discuss here measurements of such effects observed on an electron beam accelerated in a CLIC prototype structure. Read More

We have measured the ratio $\sigma(e^+e^-\rightarrow\pi^+\pi^-\gamma)/\sigma(e^+e^-\rightarrow \mu^+\mu^-\gamma)$, with the KLOE detector at DA$\Phi$NE for a total integrated luminosity of $\sim$ 240 pb$^{-1}$. From this ratio we obtain the cross section $\sigma(e^+e^-\rightarrow\pi^+\pi^-)$. From the cross section we determine the pion form factor $|F_\pi|^2$ and the two-pion contribution to the muon anomaly $a_\mu$ for $0. Read More

The ratio R_{\eta}=\Gamma(\eta -> \pi^+\pi^-\gamma)/\Gamma(\eta -> \pi^+\pi^-\pi^0) has been measured by analyzing 22 million \phi \to \eta \gamma decays collected by the KLOE experiment at DA\PhiNE, corresponding to an integrated luminosity of 558 pb^{-1}. The \eta \to \pi^+\pi^-\gamma proceeds both via the \rho resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, R_{\eta}= 0. Read More

We report the measurement of the ratio $\Gamma(\eta \to \pi^+\pi^-\gamma)/\Gamma(\eta \to \pi^+\pi^-\pi^0)$ analyzing a large sample of $\phi \to \eta \gamma$ decays recorded with the KLOE experiment at the DA$\Phi$NE $e^+ e^-$ collider, corresponding to an integrated luminosity of 558 pb$^{-1}$. The $\eta \to \pi^+\pi^-\gamma$ process is supposed to proceed both via a resonant contribution, mediated by the $\rho$ meson, and a non resonant direct term, connected to the box anomaly. The presence of the direct term affects the partial width value. Read More

2011Jul
Authors: P. Adlarson, C. Adolph, W. Augustyniak, W. Bardan, M. Bashkanov, T. Bednarski, F. S. Bergmann, M. Berłowski, H. Bhatt, K. -T. Brinkmann, M. Büscher, H. Calén, H. Clement, D. Coderre, E. Czerwiński, E. Doroshkevich, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Föhl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, C. -O. Gullström, C. Hanhart, L. Heijkenskjöld, J. Heimlich, V. Hejny, F. Hinterberger, M. Hodana, B. Höistad, M. Jacewicz, A. Jany, B. R. Jany, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, O. Khakimova, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Kłos, F. Kren, W. Krzemień, P. Kulessa, A. Kupść, K. Lalwani, S. Leupold, B. Lorentz, A. Magiera, R. Maier, B. Mariański, P. Marciniewski, U. -G. Meißner, M. Mikirtychiants, H. -P. Morsch, P. Moskal, B. K. Nandi, S. Niedźwiecki, H. Ohm, A. Passfeld, C. Pauly, E. Perez del Rio, T. Petri, Y. Petukhov, N. Piskunov, P. Pluciński, P. Podkopał, A. Povtoreyko, D. Prasuhn, A. Pricking, K. Pysz, A. Pyszniak, T. Rausmann, C. F. Redmer, J. Ritman, A. Roy, Z. Rudy, S. Sawant, S. Schadmand, A. Schmidt, T. Sefzick, V. Serdyuk, N. Shah, M. Siemaszko, R. Siudak, T. Skorodko, M. Skurzok, J. Smyrski, V. Sopov, R. Stassen, J. Stepaniak, G. Sterzenbach, H. Stockhorst, F. Stollenwerk, A. Szczurek, A. Täschner, C. Terschlüsen, T. Tolba, A. Trzciński, R. Varma, P. Vlasov, G. J. Wagner, W. Węglorz, A. Winnemöller, A. Wirzba, M. Wolke, A. Wrońska, P. Wüstner, P. Wurm, X. Yuan, L. Yurev, J. Zabierowski, C. Zheng, M. J. Zieliński, W. Zipper, J. Złomańczuk, P. Żuprański

An exclusive measurement of the decay eta --> pi+ pi- gamma has been performed at the WASA facility at COSY. The eta mesons were produced in the fusion reaction pd --> 3He X at a proton beam momentum of 1.7 GeV/c. Read More

The processes $e^+e^-\to e^+e^-X$, with $X$ being either the $\eta$ meson or $\pi^0\pi^0$, are studied at DA$\Phi$NE, with $e^+e^-$ beams colliding at $\sqrt{s}\simeq1$ GeV, below the $\phi$ resonance peak. The data sample is from an integrated luminosity of 240 pb$^{-1}$, collected by the KLOE experiment without tagging of the outgoing $e^+e^-$. Preliminary results are presented on the observation of the $\gamma\gamma\to\eta$ process, with both $\eta\to\pi^+\pi^-\pi^0$ and $\eta\to\pi^0\pi^0\pi^0$ channels, and the evidence for $\gamma\gamma\to\pi^0\pi^0$ production at low $\pi^0\pi^0$ invariant mass. Read More

2011Jul

The reaction pp->pppi0pi0 has been investigated at a beam energy of 1.4 GeV using the WASA-at-COSY facility. The total cross section is found to be (324 +- 21_systematic +- 58_normalization) mub. Read More

We report the first observation of the rare eta->e+e-e+e- decay based on 1.7 fb^{-1} collected by the KLOE experiment at the DAFNE phi-factory. The selection of the e+e-e+e- final state is fully inclusive of radiation. Read More

2011Apr
Authors: P. Adlarson, C. Adolph, W. Augustyniak, V. Baru, M. Bashkanov, F. S. Bergmann, M. Berlowski, H. Bhatt, K. -T. Brinkmann, M. Buescher, H. Calen, H. Clement, D. Coderre, E. Czerwinski, E. Doroshkevich, C. Ekstrom, R. Engels, W. Erven, W. Eyrich, P. Fedorets, K. Foehl, K. Fransson, F. Goldenbaum, P. Goslawski, K. Grigoryev, V. Grishina, C. -O. Gullstrom, J. Hampe, C. Hanhart, L. Heijkenskj, V. Hejny, F. Hinterberger, M. Hodana, B. Hoistad, M. Jacewicz, M. Janusz, A. Jany, B. R. Jany, L. Jarczyk, J. Jaus, T. Johansson, B. Kamys, G. Kemmerling, O. Khakimova, A. Khoukaz, S. Kistryn, J. Klaja, H. Kleines, B. Klos, F. Kren, W. Krzemien, P. Kulessa, S. Kullander, A. Kupsc, K. Lalwani, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, P. Moskal, H. -P. Morsch, B. K. Nandi, H. Ohm, A. Passfeld, C. Pauly, E. Perez del Rio, Y. Petukhov, N. Piskunov, P. Plucinski, P. Podkopal, A. Povtoreyko, D. Prasuhn, A. Pricking, K. Pysz, T. Rausmann, C. F. Redmer, J. Ritman, A. Roy, R. J. M. Y. Ruber, Z. Rudy, S. Schadmand, A. Schmidt, W. Schroeder, T. Sefzick, V. Serdyuk, N. Shah, M. Siemaszko, R. Siudak, T. Skorodko, M. Skurzok, J. Smyrski, V. Sopov, R. Stassen, J. Stepaniak, G. Sterzenbach, H. Stockhorst, H. Stroeher, A. Szczurek, A. Taeschner, T. Tolba, A. Trzcinski, R. Varma, P. Vlasov, G. J. Wagner, W. Weglorz, A. Winnemoeller, A. Wirzba, M. Wolke, A. Wronska, P. Wuestner, P. Wurm, L. Yurev, J. Zabierowski, M. J. Zielinski, W. Zipper, J. Zlomanczuk, P. Zupranski

We report on a high-statistics measurement of the basic double pionic fusion reaction $pn \to d\pi^0\pi^0$ over the energy region of the so-called ABC effect, a pronounced low-mass enhancement in the $\pi\pi$-invariant mass spectrum. The measurements were performed with the WASA detector setup at COSY. The data reveal the ABC effect to be associated with a Lorentzian shaped energy dependence in the integral cross section. Read More

First exclusive data for the $pp \to nn\pi^+\pi^+$ reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of $T_p$ = 1.1 GeV. Total and differential cross sections disagree with theoretical calculations, which predict the $\Delta\Delta$ excitation to be the dominant process at this beam energy. Read More

2010Jul
Authors: D. Babusci, C. Bini, F. Bossi, G. Isidori, D. Moricciani, F. Nguyen, P. Raimondi, G. Venanzoni, D. Alesini, F. Archilli, D. Badoni, R. Baldini-Ferroli, M. Bellaveglia, G. Bencivenni, M. Bertani, M. Biagini, C. Biscari, C. Bloise, V. Bocci, R. Boni, M. Boscolo, P. Branchini, A. Budano, S. A. Bulychjev, B. Buonomo, P. Campana, G. Capon, M. Castellano, F. Ceradini, E. Chiadroni, P. Ciambrone, L. Cultrera, E. Czerwinski, E. Dané, G. Delle Monache, E. De Lucia, T. Demma, G. De Robertis, A. De Santis, G. De Zorzi, A. Di Domenico, C. Di Donato, B. Di Micco, E. Di Pasquale, G. Di Pirro, R. Di Salvo, D. Domenici, A. Drago, M. Esposito, O. Erriquez, G. Felici, M. Ferrario, L. Ficcadenti, D. Filippetto, S. Fiore, P. Franzini, G. Franzini, A. Gallo, G. Gatti, P. Gauzzi, S. Giovannella, A. Ghigo, F. Gonnella, E. Graziani, S. Guiducci, F. Happacher, B. Höistad, E. Iarocci, M. Jacewicz, T. Johansson, W. Kluge, V. V. Kulikov, A. Kupsc, J. Lee Franzini, C. Ligi, F. Loddo, P. Lukin, F. Marcellini, C. Marchetti, M. A. Martemianov, M. Martini, M. A. Matsyuk, G. Mazzitelli, R. Messi, C. Milardi, M. Mirazzita, S. Miscetti, G. Morello, P. Moskal, S. Müeller, S. Pacetti, G. Pancheri, E. Pasqualucci, M. Passera, A. Passeri, V. Patera, A. D. Polosa, M. Preger, L. Quintieri, A. Ranieri, P. Rossi, C. Sanelli, P. Santangelo, I. Sarra, M. Schioppa, B. Sciascia, M. Serio, F. Sgamma, M. Silarski, B. Spataro, A. Stecchi, A. Stella, S. Stucci, C. Taccini, S. Tomassini, L. Tortora, C. Vaccarezza, R. Versaci, W. Wislicki, M. Wolke, J. Zdebik, M. Zobov

This document reviews the physics program of the KLOE-2 detector at DA$\Phi$NE upgraded in energy and provides a simple solution to run the collider above the $\phi$-peak (up to 2, possibly 2.5 GeV). It is shown how a precise measurement of the multihadronic cross section in the energy region up to 2 (possibly 2. Read More

We have measured the cross section of the radiative process e+e- -> pi+pi-gamma with the KLOE detector at the Frascati phi-factory DAPHNE, from events taken at a CM energy W=1 GeV. Initial state radiation allows us to obtain the cross section for e+e- -> pi+pi-, the pion form factor |F_pi|^2 and the dipion contribution to the muon magnetic moment anomaly, Delta a_mu^{pipi} = (478.5+-2. Read More

The status of the R&D on the Cylindrical-GEM (CGEM) detector foreseen as Inner Tracker for KLOE-2, the upgrade of the KLOE experiment at the DAFNE phi-factory, will be presented. The R&D includes several activities: i) the construction and complete characterization of the full-size CGEM prototype, equipped with 650 microns pitch 1-D longitudinal strips; ii) the study of the 2-D readout with XV patterned strips and operation in magnetic field (up to 1.5T), performed with small planar prototypes in a dedicated test at the H4-SPS beam facility; iii) the characterization of the single-mask GEM technology for the realization of large-area GEM foils. Read More

Investigation at a $\phi$--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta$^\prime$ mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the $e^+ e^-$ physics in the continuum with the measurements of (multi)hadronic cross sections and the study of gamma gamma processes. Read More

The cross sections of the pd -> 3He eta, pd -> 3He pi0 pi0 pi0 and pd -> 3He pi+ pi- pi0 reactions have been measured at beam kinetic energies T_p= 1360 MeV and T_p= 1450 MeV using the CELSIUS/WASA detector setup. At both energies, the differential cross section dsigma/dOmega of the eta meson in the pd -> 3He eta reaction shows a strong forward-backward asymmetry in the CMS. The ratio between the pd -> 3He pi+ pi- pi0 and the pd -> 3He pi0 pi0 pi0 cross sections has been analysed in terms of isospin amplitudes. Read More

The cross section for the pd --> ^3He eta pi0 reaction has been measured at a beam energy of 1450 MeV using the WASA detector at the CELSIUS storage ring and detecting one ^3He and four photons from the decays of the two photons. The data indicate that the production mechanism involves the formation of the Delta(1232) isobar. Although the beam energy does not allow the full peak of this resonance to be seen, the invariant masses of all three pairs of final state particles are well reproduced by a phase space Monte Carlo simulation weighted with the p-wave factor of the square of the pi^0 momentum in the ^3Hepi^0 system. Read More

We update the values of the eta-eta' mixing angle and of the eta' gluonium content by fitting our measurement R_phi = BR(phi to eta' gamma)/ BR(phi to eta gamma) together with several vector meson radiative decays to pseudoscalars (V to P gamma), pseudoscalar mesons radiative decays to vectors (P to V gamma) and the eta' to gamma gamma, pi^0 to gamma gamma widths. From the fit we extract a gluonium fraction of Z^2_G = 0.12 +- 0. Read More

The results from the first kinematically complete measurement of the dd --> 4Hepipi reaction are reported. The aim was to investigate a long standing puzzle regarding the origin of the peculiar pipi-invariant mass distributions appearing in double pion production in light ion collisions, the so-called ABC effect. The measurements were performed at the incident deuteron energies of 712 MeV and 1029 MeV, with the WASA detector assembly at CELSIUS in Uppsala, Sweden. Read More

The production of $\omega$ mesons in the $pd \to{}^3$He$ \omega$ reaction has been studied at two energies near the kinematic threshold, $T_p=1450$ MeV and $T_p=1360$ MeV. The differential cross section was measured as a function of the $\omega$ cm angle at both energies over the whole angular range. Whereas the results at 1360 MeV are consistent with isotropy, strong rises are observed near both the forward and backward directions at 1450 MeV. Read More

The WASA 4pi multidetector system, aimed at investigating light meson production in light ion collisions and eta meson rare decays at the CELSIUS storage ring in Uppsala is presented. A detailed description of the design, together with the anticipated and achieved performance parameters are given. Read More

These are the proceedings of the Second International Workshop on Eta Meson Physics held in May 10-11, 2007, at the resort Peniscola in Spain. The workshop was focused on topics regarding eta and eta' -meson production and decays physics of common interest in the EU EtaMesonNet network. Read More

Decay channels of the eta meson with at least one lepton pair in the final state are discussed. Preliminary results on electron-positron pair production from the pd->He eta reaction from the WASA experiment at CELSIUS are presented. Read More

The reaction pp -> pp pi0 was studied with the WASA detector at the CELSIUS storage ring. The center of mass angular distribution of the pi0 was obtained by detection of the gamma decay products together with the two outgoing protons, and found to be anisotropic with a negative second derivative slope, in agreement with the theoretical predictions from a microscopic calculation. Read More

The cross section for prompt neutral and charged three pion production in pp interactions was measured at excess energies in the range 160 - 217 MeV. That comprises the first measurement of the pp->pp pi0pi0pi0 reaction and the comparison with the pp->pp pi+pi-pi0 reaction, in a very direct way. The experiment was performed above the eta meson production threshold and the cross section normalization was obtained from a concurrent measurement of the reaction pp->pp eta with the eta decaying into 3 pions. Read More

Exclusive measurements of the reactions $pd\to$ $^3He \pi^+ \pi^-$ and $pd\to$ $^3He \pi^0\pi^0$ have been carried out at $T_p=0.895$ GeV at the CELSIUS storage ring using the WASA detector. The $\pi^+\pi^-$ channel evidences a pronounced enhancement at low invariant $\pi\pi$ masses - as anticipated from previous inclusive measurements of the ABC effect. Read More