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291 results on '"L., Venturelli"'

51. Sub-Doppler Two-Photon Laser Spectroscopy of Antiprotonic Helium and the Antiproton-to-Electron Mass Ratio

Author: L. Venturelli, S. Friedreich, Andreas Dax, Ryugo S. Hayano, D. Barna, Anna Sótér, T. Pask, Dezso Horvath, E. Widmann, Masaki Hori, B. Juhász, and Nicola Zurlo
Subjects: Physics, chemistry.chemical_element, Atomic and Molecular Physics, and Optics, Spectral line, symbols.namesake, chemistry, Antiproton, Antimatter, symbols, Physics::Accelerator Physics, Physics::Atomic Physics, Atomic physics, Spectroscopy, Antiprotonic helium, Doppler effect, Helium, Doppler broadening
Abstract: The ASACUSA collaboration of CERN has recently irradiated antiprotonic helium atoms with two counter-propagating laser beams. This excited some non-linear two-photon transitions of the antiproton at the deep UV wavelengths λ = 139.8-197.0 nm. The counterpropagating geometry of the laser beams reduced the thermal Doppler broadening of the observed resonances. Their narrow spectral lines allowed the measurement of three transition frequencies with fractional precisions of 2.3-5 parts in 10 9 . By comparing the results with three-body QED calculations, the antiproton-to-electron mass ratio was derived as 1836.1526736(23).
Published: 2013

52. Buffer-gas cooling of antiprotonic helium to 1.5 to 1.7 K, and antiproton-to-electron mass ratio

Author: Ryugo S. Hayano, Hiroyuki Yamada, Masaki Hori, Takumi Kobayashi, K. Todoroki, D Horváth, Hossein Aghai-Khozani, L. Venturelli, Y. Murakami, D. Barna, Anna Sótér, and Andreas Dax
Subjects: Antiparticle, ANTIHYDROGEN, Helium atom, Proton, Buffer gas, TRANSITIONS, Electron, PROTON, 01 natural sciences, Nuclear physics, chemistry.chemical_compound, 0103 physical sciences, 010306 general physics, Spectroscopy, LASER SPECTROSCOPY, Antiprotonic helium, Physics, ATOMIC MASS, HYDROGEN, CONSTANTS, FORCES, CHARGE, CPT, Multidisciplinary, 010308 nuclear & particles physics, chemistry, Antiproton, Atomic physics
Abstract: Exotic molecule tests fundamental symmetry Spectroscopy of exotic molecules can offer insight into fundamental physics. Hori et al. studied the transition frequencies of an unusual helium atom in which one of the two electrons was substituted by an antiproton, the negatively charged antiparticle partner of the proton (see the Perspective by Ubachs). The antiprotonic helium was cooled down to low temperatures to allow the frequencies to be measured with high precision. The extracted mass of the antiproton (relative to the electron mass) was in good agreement with previous measurements of the proton mass. This finding is in keeping with the implications of the combined charge, parity, and time-reversal symmetry of physical laws. Science , this issue p. 610 ; see also p. 546
Published: 2016

53. Instrumentation for measurement of in-flight annihilations of 130 keV antiprotons on thin target foils

Author: M. Corradini, Hossein Aghai-Khozani, E. Lodi-Rizzini, Ryugo S. Hayano, L. Venturelli, V. Prest, D. De Salvador, Anna Sótér, K. Todoroki, L. Vallazza, Valerio Mascagna, M. Leali, D. Barna, and Masaki Hori
Subjects: Physics, Nuclear and High Energy Physics, Annihilation, Nuclear cross section, 010308 nuclear & particles physics, Antiproton, Kinetic energy, 01 natural sciences, Nuclear physics, Time of flight, symbols.namesake, Pion, 0103 physical sciences, symbols, Physics::Accelerator Physics, Rutherford scattering, Instrumentation, Atomic physics, 010306 general physics, Beam (structure)
Abstract: We describe the instrumentation for an experiment to measure the cross sections of antiprotons with kinetic energies of 130±10 keV annihilating on carbon, palladium, and platinum target foils of sub-100 nm thicknesses. A 120 ns long pulsed beam containing 10 5 – 10 6 antiprotons was allowed to traverse the foils, and the signal annihilations that resulted from this were isolated using a time-of-flight method. Backgrounds arose from Rutherford scattering of the antiprotons off the target foils, their annihilations in the target chamber walls, and π → μ → e decay of the charged pions that emerged from the annihilations. Some antiprotons slowed down and annihilated in the contamination on the target surfaces. This reduced the signal-to-background ratio of the measurement.
Published: 2016

54. Towards Measuring the Ground State Hyperfine Splitting of Antihydrogen -- A Progress Report

Author: M. C. Simon, Yasuyuki Matsuda, S. Vamosi, A. A. Capon, Sebastian Lehner, P. Dupre, M. Leali, Chloé Malbrunot, Yasunori Yamazaki, Naofumi Kuroda, E. Lodi Rizzini, S. Van Gorp, B. Kolbinger, O. Massiczek, Stefan Ulmer, C. Sauerzopf, Y. Higashi, Eberhard Widmann, L. Venturelli, Yugo Nagata, H. Breuker, Yasuyuki Kanai, C. Kaga, Valerio Mascagna, M. Diermaier, M. Tajima, Ken Suzuki, B. Radics, Hiroyuki Higaki, Johann Zmeskal, and D. J. Murtagh
Subjects: Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, FOS: Physical sciences, Scintillator, 01 natural sciences, Field-ioniser, Atomic and Molecular Physics, 0103 physical sciences, Principal quantum number, Precision spectroscopy, Detectors and Experimental Techniques, Physical and Theoretical Chemistry, 010306 general physics, Spectroscopy, Antihydrogen, Hyperfine structure, Physics, 010308 nuclear & particles physics, Detector, Instrumentation and Detectors (physics.ins-det), Condensed Matter Physics, Atomic and Molecular Physics, and Optics, CPT, PIPS, Atomic physics, and Optics, Ground state, Beam (structure)
Abstract: We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector., Comment: 5 pages, 2 figures, 6th International Symposium on Symmetries in Subatomic Physics (SSP2015)
Published: 2016
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55. Direct detection of antihydrogen atoms using a BGO crystal

Author: L. Venturelli, Mascagna, H. A. Torii, M. Leali, Yasuyuki Matsuda, Yasunori Yamazaki, M. Tajima, Yugo Nagata, E. Lodi-Rizzini, Naofumi Kuroda, Miki Ohtsuka, and N. Zurlo
Subjects: Physics::General Physics, Antimatter, Nuclear and High Energy Physics, Cosmic ray, 01 natural sciences, Spectral line, Nuclear physics, Pion, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics, Antihydrogen, Instrumentation, Physics, Cosmic ray background suppression, Detector, Inorganic scintillator, Annihilation, 010308 nuclear & particles physics, Atomic physics
Abstract: The ASACUSA collaboration has developed a detector consisting of a large size BGO crystal to detect an atomic antihydrogen beam, and performed the direct detection of antihydrogen atoms. Energy spectra from antihydrogen annihilation on the BGO crystal are discussed in comparison to simulation results from the GEANT4 toolkit. Background mainly originating from cosmic rays were strongly suppressed by analyzing the energy deposited in the BGO and requiring a multiplicity of charged pions. Thus antihydrogen events were identified.
Published: 2016

56. The ASACUSA CUSP: an antihydrogen experiment

Author: N. Kuroda, S. Ulmer, D. J. Murtagh, S. Van Gorp, Y. Nagata, M. Diermaier, S. Federmann, M. Leali, C. Malbrunot, V. Mascagna, O. Massiczek, K. Michishio, T. Mizutani, A. Mohri, H. Nagahama, M. Ohtsuka, B. Radics, S. Sakurai, C. Sauerzopf, K. Suzuki, M. Tajima, H. A. Torii, L. Venturelli, B. Wünschek, J. Zmeskal, N. Zurlo, H. Higaki, Y. Kanai, E. Lodi Rizzini, Y. Nagashima, Y. Matsuda, E. Widmann, and Y. Yamazaki
Published: 2015

57. In-flight antiproton annihilation on nuclei at low energies

Author: M. Prest, K. Todoroki, E. Lodi-Rizzini, L. Venturelli, A. Mozzanica, Anna Sótér, M. Leali, Takumi Kobayashi, Maurizio Corradini, E. Vallazza, Nicola Zurlo, Masaki Hori, and Valerio Mascagna
Subjects: Physics, antiproton, annihilation, cross section, Nuclear and High Energy Physics, Particle physics, Annihilation, Large Hadron Collider, Physics::Instrumentation and Detectors, chemistry.chemical_element, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Nuclear physics, Cross section (physics), chemistry, Antiproton, Physics::Accelerator Physics, Physical and Theoretical Chemistry, Experimental methods, Tin, Beam (structure)
Abstract: The results of the annihilation cross sections measurement of 5.3 MeV antiprotons on nickel, tin, platinum and Mylar targets performed by the ASACUSA Collaboration at CERN are presented and compared with the existing data and models. From the experimental point of view the presented data are the first measurement of antinucleon annihilation cross sections at low energies obtained with a pulsed beam. This results open the road for the next measurements at the very low energies of the order of 100 keV that are in progress by the ASACUSA Collaboration. The experimental method foreseen for the 100 keV measurement is illustrated.
Published: 2011

58. Beam profile monitor for annihilation cross section measurements of antiprotons at 100 keV

Author: Takumi Kobayashi, K. Todoroki, Anna Sótér, Nicola Zurlo, Valerio Mascagna, Evandro Lodi Rizzini, Ryugo S. Hayano, M. Leali, Maurizio Corradini, Masaki Hori, and L. Venturelli
Subjects: Physics, Nuclear and High Energy Physics, Secondary electron emission, Annihilation, Large Hadron Collider, Beam profile monitor, Antiproton annihilation cross section, Atomic spectroscopy, Condensed Matter Physics, Kinetic energy, Atomic and Molecular Physics, and Optics, Nuclear physics, Antiproton Decelerator, Antiproton, ASACUSA, Physical and Theoretical Chemistry, Atomic and Molecular Physics, Secondary emission, Physics::Accelerator Physics, and Optics, Atomic physics, Beam (structure)
Abstract: The ASACUSA (the Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration is planning to measure the cross sections of antiproton annihilations at kinetic energy 100 keV on targets of various mass numbers (C, Ni, Sn, and Pt) using the Antiproton Decelerator (AD) of CERN. No previous measurement exists in this region where the A-dependence of the cross section is expected to deviate from the A$^{\frac{2}{3}}$ (Batty et al, Nucl Phys A 689:721, 2001) as reported by the Obelix collaboration. A beam profile monitor based on secondary electron emission with a grid of electrode pads fabricated on an FR4-type glass-epoxy circuit board was developed for this measurement. The advantage of this kind of detector is that it is simple, lightweight, and low cost. It was used to measure the spatial profile of 100-ns-long beam pulses containing > 6 × 104 antiprotons with an active area of 40 mm × 40 mm and a spatial resolution of 4 mm.
Published: 2011

59. Mass discrimination using double-sided silicon microstrip detectors for pions and protons at intermediate energies

Author: Paolo Camerini, Rinaldo Rui, L. Venturelli, L. Celano, Richard Wheadon, M. De Palma, N. Grion, P. Bottan, L. Fiore, V. Paticchio, F. De Mori, P., Bottan, Camerini, Paolo, L., Celano, F., DE MORI, M., DE PALMA, L., Fiore, N., Grion, V., Paticchio, Rui, Rinaldo, L., Venturelli, and R., Wheadon
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Silicon, Physics::Instrumentation and Detectors, Nuclear Theory, Detector, chemistry.chemical_element, Ranging, Integrated circuit, law.invention, Nuclear physics, Pion, chemistry, law, Silicon detector, Mass discrimination, High Energy Physics::Experiment, Nuclear Experiment, Instrumentation, Silicon microstrip detectors
Abstract: Prototype silicon detector modules for the vertex detector of the FINUDA experiment were tested at TRIUMF using pions and protons at 270 and 408 MeV/c in order to study their use for mass discrimination based on energy deposition. The detector modules were constructed using double-sided silicon detectors based on the ALEPH design, read out by VA1 integrated circuits. The test modules and apparatus are described, details of the data analysis are discussed, and the results are presented together with GEANT simulations. Particular attention is given to the detector response for the various particles, with signals ranging from the minimum-ionising pions at 408 MeV/c up to 20 times minimum-ionising for the protons at 270 MeV/c. ( 1999 Elsevier Science B.V. All rights reserved.
Published: 1999

60. The mechanisms of antihydrogen formationThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at University of Windsor, Windsor, Ontario, Canada on 21–26 July 2008

Author: N. Zurlo, L. Venturelli, and E. Lodi Rizzini
Subjects: Nuclear physics, Physics, Large Hadron Collider, Antiproton, Radiative capture, General Physics and Astronomy, Windsor, Antihydrogen, Penning trap, Ontario canada, Preliminary analysis
Abstract: Some years have passed since the report of the first production of cold antihydrogen by the Athena Collaboration and the Atrap Collaboration at CERN, but no clear answer has been given about the roles of the two mechanisms responsible for antihydrogen formation. A new preliminary analysis of the data acquired by the Athena Collaboration in different experimental conditions seems to suggest that three-body recombination mechanism is dominant in the first tens of seconds of the overlapping of the injected antiproton cloud with the positron plasma in the nested Penning trap, while radiative capture starts to become dominant afterwards.
Published: 2009

61. Antiproton slowing down, capture, and decay in low-pressure helium gas

Author: F. Tosello, S. Tessaro, N. Semprini Cesari, L. Santi, M. Bargiotti, O.E. Gorchakov, M. Leali, Mauro Villa, A. Grasso, L. Ferrero, R. Garfagnini, Nicola Zurlo, I. Massa, G. Piragino, S. De Castro, Pietro Faccioli, Antonio Zoccoli, Antonietta Donzella, F. Grimaldi, A. Bertin, C. Petrascu, L. Venturelli, Roberto Spighi, M. Corradini, Marco Bruschi, Gianfranco Zosi, A. Vitale, M.P. Bussa, G.B. Pontecorvo, F. Balestra, G. V. Margagliotti, Stefania Vecchi, Andrea Bianconi, M. Poli, M. Capponi, C. Guaraldo, A.M. Rozhdestvensky, Benedetto Giacobbe, V.I. Tretyak, A. Maggiora, E. Lodi Rizzini, Massimo Piccinini, Laura Fabbri, O. Y. Denisov, L. Busso, A., Bianconi, M., Corradini, A., Donzella, M., Leali, E., Lodirizzini, L., Venturelli, N., Zurlo, M., Bargiotti, A., Bertin, M., Bruschi, M., Capponi, S., DE CASTRO, L., Fabbri, P., Faccioli, B., Giacobbe, F., Grimaldi, I., Massa, M., Piccinini, N., Semprinicesari, R., Spighi, S., Vecchi, M., Villa, A., Vitale, A., Zoccoli, O. E., Gorchakov, G. B., Pontecorvo, A. M., Rozhdestvensky, V. I., Tretyak, M., Poli, C., Guaraldo, C., Petrascu, F., Balestra, M. P., Bussa, L., Busso, O. Y., Denisov, L., Ferrero, R., Garfagnini, A., Grasso, A., Maggiora, G., Piragino, F., Tosello, G., Zosi, Margagliotti, Giacomo, L., Santi, S., Tessaro, A. Bianconi, M. Corradini, A. Donzella, M. Leali, E. Lodi Rizzini, L. Venturelli, N. Zurlo, M. Bargiotti, A. Bertin, M. Bruschi, M. Capponi, S. De Castro, L. Fabbri, P. Faccioli, B. Giacobbe, F. Grimaldi, I. Massa, M. Piccinini, N. Semprini Cesari, R. Spighi, S. Vecchi, M. Villa, A. Vitale, A. Zoccoli, O. E. Gorchakov, G. B. Pontecorvo, A. M. Rozhdestvensky, V. I. Tretyak, M. Poli, C. Guaraldo, C. Petrascu, F. Balestra, M. P. Bussa, 6 L. Busso, O. Y. Denisov, L. Ferrero, R. Garfagnini, A. Grasso, A. Maggiora, G. Piragino, F. Tosello, G. Zosi, G. Margagliotti, L. Santi, and S. Tessaro
Subjects: H-2, Physics, COLLISIONS, HE, Hydrogen, Monte Carlo method, Extrapolation, Antiproton, chemistry.chemical_element, HYDROGEN, Atomic and Molecular Physics, and Optics, ATOMS, Nuclear physics, NUCLEAR STOPPING POWER, Deuterium, chemistry, Ionization, IONIZATION, Stopping power (particle radiation), Atomic physics, Helium
Abstract: Data on p¯ slowing down and capture in helium at 1 and 0.2 mb at room temperature are presented and compared to the corresponding previously publicated data in molecular hydrogen and deuterium. A Monte Carlo simulation containing a low-energy extrapolation of measured p¯electronic stopping power in helium gas,screened Rutherford collisions, and simple cascade mechanisms is able to reproduce the gross features of the data, but cannot explain some nontrivial details of the measured distributions.
Published: 2004

62. Antiproton stopping power in He in the energy range 1-KeV - 900-keV and the Barkas effect

Author: Maurizio Piccinini, S. De Castro, F. Tosello, S. Tessaro, C. Guaraldo, G.B. Pontecorvo, A. Grasso, L. Ferrero, Nicola Zurlo, Mauro Villa, M. Bargiotti, G. V. Margagliotti, M. Poli, A. Bertin, C. Petrascu, Gianfranco Zosi, Andrea Bianconi, I. Massa, M. Leali, A.M. Rozhdestvensky, E. Lodi Rizzini, F. Balestra, M.P. Bussa, Stefania Vecchi, Laura Fabbri, O. Y. Denisov, R. Donà, M. Capponi, L. Busso, N. Semprini Cesari, L. Santi, L. Venturelli, G. Piragino, Antonietta Donzella, B. Giacobbe, V.I. Tretyak, A. Vitale, Marco Bruschi, A. Maggiora, O.E. Gorchakov, R. Garfagnini, Antonio Zoccoli, Pietro Faccioli, F. Grimaldi, R. Spighi, M. Corradini, RUS, DIP. DI FISICA, DIPARTIMENTO DI FISICA E ASTRONOMIA 'AUGUSTO RIGHI', Facolta' di INGEGNERIA, SECONDA FACOLTA' DI INGEGNERIA DELL'UNIVERSITA' DI BOLOGNA CON SEDE CESENA, Da definire, AREA MIN. 02 - Scienze fisiche, E., Lodirizzini, A., Bianconi, M. P., Bussa, M., Corradini, A., Donzella, M., Leali, L., Venturelli, N., Zurlo, M., Bargiotti, A., Bertin, M., Bruschi, M., Capponi, S., DE CASTRO, R., Don, L., Fabbri, P., Faccioli, B., Giacobbe, F., Grimaldi, I., Massa, M., Piccinini, N., Semprinicesari, R., Spighi, S., Vecchi, M., Villa, A., Vitale, A., Zoccoli, O. E., Gorchakov, G. B., Pontecorvo, A. M., Rozhdestvensky, V. I., Tretyak, M., Poli, C., Guaraldo, C., Petrascu, F., Balestra, L., Busso, O. Y., Denisov, L., Ferrero, R., Garfagnini, A., Grasso, A., Maggiora, G., Piragino, F., Tosello, G., Zosi, Margagliotti, Giacomo, L., Santi, Tessaro, Susanna, E. Lodi Rizzini, A. Bianconi, M.P. Bussa, M. Corradini, A. Donzella, M. Leali, L. Venturelli, N. Zurlo, M. Bargiotti, A. Bertin, M. Bruschi, M. Capponi, S. De Castro, R. Dona, L. Fabbri, P. Faccioli, B. Giacobbe, F. Grimaldi, I. Massa, M. Piccinini, N. Semprini-Cesari, R. Spighi, S. Vecchi, M. Villa, A. Vitale, A. Zoccoli, O.E. Gorchakov, G.B. Pontecorvo, A.M. Rozhdestvensky, V. Tretyak, M. Poli, C. Guaraldo, C. Petrascu, F. Balestra, L. Busso, O.Yu. Denisov, L. Ferrero, R. Garfagnini, A. Grasso, A. Maggiora, G. Piragino, F. Tosello, G. Zosi, G. Margagliotti, L. Santi, and S. Tessaro
Subjects: Physics, Range (particle radiation), Nuclear and High Energy Physics, Proton, chemistry.chemical_element, Stopping power, Barkas, Kinetic energy, Nuclear physics, chemistry, Fundamental difference, Antiproton, Stopping power (particle radiation), Atomic physics, Helium, Energy (signal processing)
Abstract: none 46 The stopping power in helium from 1 keV kinetic energy is evaluated. Contrary to the effect observed around and below the maximum, Obelix data indicate a stopping power higher than that for proton, the difference being of the order of 15±5% at ≈700 keV. The result contributes to assert the fundamental difference between stoppings in the simplest gases (He, H2) and in solid targets below some MeV. none E. Lodi Rizzini; A. Bianconi; M.P. Bussa; M. Corradini; A. Donzella; M. Leali; L. Venturelli; N. Zurlo; M. Bargiotti; A. Bertin; M. Bruschi; M. Capponi; S. De Castro; R. Dona; L. Fabbri; P. Faccioli; B. Giacobbe; F. Grimaldi; I. Massa; M. Piccinini; N. Semprini-Cesari; R. Spighi; S. Vecchi; M. Villa; A. Vitale; A. Zoccoli; O.E. Gorchakov; G.B. Pontecorvo; A.M. Rozhdestvensky; V. Tretyak; M. Poli; C. Guaraldo; C. Petrascu; F. Balestra; L. Busso; O.Yu. Denisov; L. Ferrero; R. Garfagnini; A. Grasso; A. Maggiora; G. Piragino; F. Tosello; G. Zosi; G. Margagliotti; L. Santi; S. Tessaro E. Lodi Rizzini; A. Bianconi; M.P. Bussa; M. Corradini; A. Donzella; M. Leali; L. Venturelli; N. Zurlo; M. Bargiotti; A. Bertin; M. Bruschi; M. Capponi; S. De Castro; R. Dona; L. Fabbri; P. Faccioli; B. Giacobbe; F. Grimaldi; I. Massa; M. Piccinini; N. Semprini-Cesari; R. Spighi; S. Vecchi; M. Villa; A. Vitale; A. Zoccoli; O.E. Gorchakov; G.B. Pontecorvo; A.M. Rozhdestvensky; V. Tretyak; M. Poli; C. Guaraldo; C. Petrascu; F. Balestra; L. Busso; O.Yu. Denisov; L. Ferrero; R. Garfagnini; A. Grasso; A. Maggiora; G. Piragino; F. Tosello; G. Zosi; G. Margagliotti; L. Santi; S. Tessaro
Published: 2004

63. Two-prong πHe interactions at 106 MeV

Author: S. Baginyan, V. I. Pryanichnikov, M. Schepkin, I. A. Belolaptikov, G. B. Pontecorvo, V. Lyashenkov, Yu.A. Batusov, E. Lodi Rizzini, V.V. Ivanov, A. Maggiora, I. Gnesi, Vladimir Frolov, V.A. Panyushkin, A. Grasso, I. Smirnova, N.S. Angelov, T. Blokhintseva, M. Maggiora, D. Panzieri, L. Venturelli, N.A. Russakovich, Andrea Ferrero, A.M. Rozhdestvensky, F. Balestra, V. M. Grebenyuk, V.A. Butenko, A. Kirilov, A. Bonyushkina, L. Fava, V.A. Drozdov, V.E. Kovalenko, A. Moiseenko, Andrea Bianconi, A. Dem’yanov, Gianfranco Zosi, M.L. Colantoni, M. Chiosso, B. Parsamyan, R. Garfagnini, and G. Piragino
Subjects: Physics, Nuclear reaction, Elastic scattering, Nuclear physics, Nuclear and High Energy Physics, Helium-4, Meson, Nuclear fusion, Neutron, Atomic physics, Nucleon, Charged particle
Abstract: π-4He interactions at 106MeV, with two secondary charged particles in the final state, have been studied using a self-shunted streamer chamber in a 0.65T magnetic field and equipped with two CCD videocameras for obtaining digitized stereo-images of nuclear events occurring within the fiducial volume of the streamer chamber. Branching ratios for the various interaction channels are deduced. Evidence is presented for a reaction channel involving a γ produced in the final state, as well as for the first observation of direct Δ- -resonance production. Cross-section distributions for the elastic and quasi-elastic interaction channels are also reported.
Published: 2007

64. Operation and performance of the FAST detector at the AD machine

Author: M. Prest, Nicola Zurlo, Davide Bolognini, L. Venturelli, E. Lodi Rizzini, M. Leali, E. Vallazza, V. Mascagna, A. Mozzanica, and M. Corradini
Subjects: Physics, Nuclear and High Energy Physics, Large Hadron Collider, Physics::Instrumentation and Detectors, Detector, Scintillating tracker, antiproton decelerator, ASACUSA, multianode PMT, Cosmic ray, Atomic and Molecular Physics, and Optics, Particle detector, Antiproton Decelerator, Nuclear physics, Antiproton, Antimatter, Physics::Accelerator Physics, High Energy Physics::Experiment, Beam (structure)
Abstract: The FAST (Fiber Antiproton Scintillating Tracker) detector has been installed at the Antiproton Decelerator at the CERN PS. Its goal is the measurement of the annihilation cross section of slow antiprotons (around 5 MeV) in gaseous targets in the ASACUSA experiment. FAST has to reconstruct the charged pions tracks to identify the annihilation vertices. The detector consists of 2 axial and 4 stereo layers of scintillating fibers. Each layer is built with 1 mm 50 cm long BCF-10 fibers readout by 64 channel multianode PMTs for a total of 2688 readout channels. The anode outputs, amplified and discriminated, are sampled with a 320 MHz clock inside a Cyclone II FPGA by Altera, in order to retrieve the time information of each hit. The readout system is designed to cope with a spilled beam which lasts 250 ns every minute. The expected number of events per spill was around 10. This paper will describe the operation and the performance of the FAST detector during the tests with cosmic rays (August 2006) and during the data taking on the beam (September 2006).
Published: 2007

65. Beam Diagnostics for Measurements of In-Flight Annihilation Cross Sections of Antiprotons at 130 keV

Author: Maurizio Corradini, Valerio Mascagna, Anna Soter, Masaki Hori, E. Vallazza, Ryugo S. Hayano, L. Venturelli, E. Lodi-Rizzini, D. Barna, M. Prest, M. Leali, K. Todoroki, Takumi Kobayashi, Hossein Aghai-Khozani, and Nicola Zurlo
Subjects: Nuclear physics, Physics, Particle physics, Large Hadron Collider, Annihilation, Antiproton, Beam (structure)
Abstract: Hossein Aghai-Khozani1,2, Daniel Barna3,4, Maurizio Corradini5,6, Ryugo Hayano4, Masaki Hori1,4, Takumi Kobayashi4, Marco Leali5,6, Evandro Lodi-Rizzini5,6, Valerio Mascagna5,6, Michela Prest7,8, Anna Soter1, Koichi Todoroki4, Erik Vallazza9, Luca Venturelli5,6, and Nicola Zurlo5,6 1Max-Planck-Institut fur Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany 2Physics Department, CERN, 1211 Geneva 23, Switzerland 3Wigner Institute for Particle and Nuclear Physics, H-1525 Budapest, Hungary 4Department of Physics, University of Tokyo, Hongo7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan 5Dipartimento di Collegato di Brescia, 25133 Brescia, Italy 6INFN, Gruppo Collegato di Brescia, 25133 Brescia, Italy 7Dipartimento di Scienze Fisiche e Matematiche, Universita di Como, I-22100 Como, Italy 8INFN, Sezione di Milano Bicocca, I-20126 Milano, Italy 9INFN, Sezione di Trieste, I-34127 Trieste, Italy
Published: 2015

66. Laser Spectroscopic Study on the Highly Excited States of Antiprotonic Helium

Author: M. Hori, K. Todoroki, Takayoshi Kobayashi, N. Zurlo, D. Barna, Y. Murakami, D Horváth, R S Hayano, L. Venturelli, H. Aghai-Khozani, Anna Sótér, Andreas Dax, and Hiroyuki Yamada
Subjects: Nuclear physics, Physics, Research centre, law, Excited state, Atomic physics, Laser, Antiprotonic helium, law.invention
Abstract: T. Kobayashi1 †, D. Barna1,2, R. S. Hayano1, Y. Murakami1, K. Todoroki1, H. Yamada1, A. Dax3, L. Venturelli4,5, N. Zurlo4,5, D. Horvath2,6, H. Aghai-Khozani7,8, A. Soter7, and M. Hori7,1 1Department of Physics, University of Tokyo, Hongo, Bunkyo-ku 113-0033, Japan 2Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, Budapest, 1525, Hungary 3Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland 4Dipartimento di Ingegneria dell Informazione, Universita di Brescia, I-25123 Brescia, Italy 5INFN, Gruppo Collegato di Brescia, I-25133 Brescia, Italy 6Institute of Nuclear Research, H-4001 Debrecen, Hungary 7Max-Planck-Institut fur Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany 8CERN, CH-1211 Geneva 23, Switzerland
Published: 2015

67. Scintillating bar detector for antiproton annihilations measurements

Author: M. Corradini, M. Leali, E. Lodi Rizzini, V. Mascagna, M. Prest, E. Vallazza, and L. Venturelli
Published: 2015

68. The development of the antihydrogen beam detector and the detection of the antihydrogen atoms for in-flight hyperfine spectroscopy

Author: S. Van Gorp, Stefan Ulmer, B. Radics, Yasunori Yamazaki, Y. Abo, P. Dupre, Chloé Malbrunot, Horst Breuker, M. Tajima, M. Diermaier, Yugo Nagata, L. Venturelli, Yoshio Kanai, Johann Zmeskal, M. Leali, C. Sauerzopf, Y. Higashi, D. J. Murtagh, Shumpei Ishikawa, Hiroyuki Higaki, C. Kaga, Valerio Mascagna, Naofumi Kuroda, M. C. Simon, A. A. Capon, Yasuhiro H. Matsuda, Eberhard Widmann, and H. A. Torii
Subjects: Physics, Physics::General Physics, History, Physics::Instrumentation and Detectors, CPT symmetry, Detector, Particle detector, Computer Science Applications, Education, Nuclear physics, Physics and Astronomy (all), Physics in General, Antimatter, Physics::Atomic and Molecular Clusters, High Energy Physics::Experiment, Physics::Atomic Physics, Atomic physics, Antihydrogen, Spectroscopy, Hyperfine structure, Beam (structure)
Abstract: We have been developing ground-state antihydrogen atomic beams to test CPT symmetry via in-flight hyperfine spectroscopy. A new antihydrogen beam detector has been developed. The overview of the experiment, the detail of the detector and latest results will be presented.
Published: 2015

69. First measurement of the antiproton-nucleus annihilation cross section at 125 keV

Author: Ryugo S. Hayano, D. Seiler, M. Prest, M. Corradini, Daniel Barna, K. Todoroki, Masaki Hori, E. Lodi-Rizzini, Hossein Aghai-Khozani, M. Leali, E. Vallazza, D. De Salvador, L. Venturelli, Anna Sótér, Takayoshi Kobayashi, and Valerio Mascagna
Subjects: Physics, Nuclear reaction, Antiparticle, Nuclear and High Energy Physics, Annihilation, Cross section, Antiproton, Nuclear, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Physical and Theoretical Chemistry, Baryon, Nuclear physics, Cross section (physics), Antimatter, Atomic and Molecular Physics, Atomic physics, and Optics, Nucleon
Abstract: The first observation of in-flight antiproton-nucleus annihilation at ∼130 keV obtained with the ASACUSA detector has demonstrated that the measurement of the cross section of the process is feasible at such extremely low energies Aghai-Khozani, H., et al., Eur. Phys. J. Plus 127, 55 (2012). Here we present the results of the data analysis with the evaluations of the antiproton annihilation cross sections on carbon, palladium and platinum targets at ∼125 keV.
Published: 2015

70. Search for the pentaquark in antiproton 4He annihilation at rest

Author: Piergiorgio Cerello, G. Puddu, M. Corradini, Felice Iazzi, C. Guaraldo, Corrado Cicalo, Adriano Fontana, A.M. Rozhdestvensky, L. Busso, L. Venturelli, A. Feliciello, Alberto Masoni, D. Calvo, Aldo Zenoni, Paola Salvini, Bruno Minetti, Armando Lanaro, V.I. Tretyak, A. Maggiora, L. Ferrero, S.N. Prakhov, S. Costa, O.E. Gorchakov, R. Garfagnini, G. L. Usai, Alberto Rotondi, V. Lucherini, Antonietta Donzella, Michelangelo Agnello, O. Y. Denisov, Paolo Montagna, M.P. Bussa, L. Lavezzi, D. Panzieri, Tullio Bressani, Elena Botta, Catalina Curceanu, E. Lodi Rizzini, S. Serci, G. Bendiscioli, A. Filippi, A. Grasso, A. Panzarasa, F. Balestra, S. Marcello, G. M. Sapozhnikov, A. De Falco, P. Gianotti, and F. Tosello
Subjects: Baryon, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Antiproton, Invariant mass, Strangeness, Nuclear Experiment, Nucleon, Resonance (particle physics), Pentaquark
Abstract: A research has been made to look for a signature of the positive-strangeness baryon resonance Θ + ( 1530 ) , which is expected to decay into p K 0 . A peak is observed in the p π + π − invariant mass distribution in antiproton– 4 He annihilation reactions at rest with production of two π + π − pairs with invariant mass close to the K S 0 mass. The annihilation reactions on 4 He can involve two to four nucleons producing an energy blob characterized by high strangeness content. The peak is centred around 1560.0 ± 3.7 MeV and its width is very narrow. The statistical significance is 2.7; this value is considered of not sufficient significance to claim support of the Θ + . The data were collected with the Obelix spectrometer at the LEAR machine of CERN.
Published: 2006

71. φ and ω meson production in annihilation and the OZI rule

Author: M. Corradini, Alberto Masoni, D. Calvo, F. Nichitiu, L. Venturelli, A. Grasso, G. Pauli, A. Filippi, R. Garfagnini, Paolo Montagna, Elena Botta, F. Tosello, S. Tessaro, Michelangelo Agnello, Marco Bruschi, Antonio Zoccoli, S. Marcello, Umberto Marini Bettolo Marconi, T. D. Galli, Tullio Bressani, V.I. Tretyak, A. Saino, U. Gastaldi, A. Maggiora, V. Lucherini, F. D'Isep, V. Filippini, L. Fava, M. Morando, F. Balestra, Paola Gianotti, Aldo Zenoni, G. Zosi, L. Busso, M. Nupieri, Roberto Spighi, Bruno Minetti, M.P. Bussa, P. Cerello, M.G. Sapozhnikov, S. De Castro, Stefania Vecchi, A. Bertin, A.M. Rozhdestvensky, S. Costa, G. L. Usai, A. Vitale, P.P. Temnikov, Felice Iazzi, Corrado Cicalo, Massimo Piccinini, Adriano Fontana, M. Capponi, N. Semprini Cesari, B. Cereda, S. Serci, L. Santi, Mauro Villa, V.G. Ableev, Armando Lanaro, L. Ferrero, Alberto Rotondi, G. Puddu, E. Rossetto, D. Panzieri, G. V. Margagliotti, Alessandro Feliciello, C. Guaraldo, G. Bendiscioli, G.C. Bonazzola, Paola Salvini, Antonietta Donzella, Benedetto Giacobbe, E. Lodi Rizzini, V. G., Ableev, M., Agnello, F., Balestra, G., Bendiscioli, A., Bertin, G. C., Bonazzola, E., Botta, T., Bressani, M., Bruschi, M. P., Bussa, L., Busso, D., Calvo, M., Capponi, B., Cereda, P., Cerello, C., Cicalò, M., Corradini, S., Costa, S., De Castro, F., D'Isep, A., Donzella, L., Fava, A., Feliciello, L., Ferrero, A., Filippi, V., Filippini, A., Fontana, T. D., Galli, R., Garfagnini, U., Gastaldi, B., Giacobbe, P., Gianotti, A., Grasso, C., Guaraldo, F., Iazzi, A., Lanaro, E., Lodi Rizzini, V., Lucherini, A., Maggiora, S., Marcello, U., Marconi, Margagliotti, Giacomo, A., Masoni, B., Minetti, P., Montagna, M., Morando, F., Nichitiu, M., Nupieri, D., Panzieri, G., Pauli, M., Piccinini, G., Puddu, E., Rossetto, A., Rotondi, A. M., Rozhdestvensky, A., Saino, P., Salvini, L., Santi, M. G., Sapozhnikov, N., Semprini Cesari, S., Serci, R., Spighi, P., Temnikov, S., Tessaro, F., Tosello, V. I., Tretyak, G., Usai, S., Vecchi, L., Venturelli, M., Villa, A., Vitale, A., Zenoni, A., Zoccoli, and G., Zosi
Subjects: Quark, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, 4-QUARK EXOTICS, Elementary particle, Antineutron, Omega, Nuclear physics, OZI rule, Mass spectrum
Abstract: The φπ + /ωπ + ratio from n ¯ p annihilations on a liquid hydrogen target, for n ¯ momenta between 64 and 297 MeV/ c , was measured using the OBELIX spectrometer at LEAR. The ratio R ( ϕ π / ω π ) = σ ( n ¯ p → ϕ π + ) / σ ( n ¯ p → ω π + ) turned out 0.110±0.015 stat ±0.006 syst . Implications of this result on the OZI rule are discussed.
Published: 1994

72. Production and decay of $\eta^{\prime}(958)$ and $\eta (1440)$ in $\bar p p$ annihilation at rest

Author: M. Corradini, F. Nichitiu, A.M. Rozhdestvensky, G. Pauli, Paolo Montagna, Paola Salvini, M. Lombardi, Massimo Piccinini, El Rizzini, Roberto Spighi, F. Tosello, Ableev, A. Vitale, S. Decastro, O.E. Gorchakov, D. Galli, A M Rosca, C. Guaraldo, Lucherini, M.G. Sapozhnikov, Alberto Masoni, G. Maron, D. Calvo, L. Santi, O. Y. Denisov, Bruno Minetti, Antonietta Donzella, Felice Iazzi, Armando Lanaro, L. Fava, G. Bendiscioli, Umberto Marini Bettolo Marconi, C. Scoglio, F. Balestra, Nicola Semprini-Cesari, L. Busso, Filippini, C. Cicalo, A. Grasso, E. Rossetto, M. Capponi, M. Poli, Mauro Villa, L. Ferrero, G. Vedovato, L. Vannucci, P. Gianotti, S. Serci, S. Tessaro, Benedetto Giacobbe, Alberto Rotondi, A. Collamati, Tullio Bressani, F. Vigotti, C. Petrascu, D. Panzieri, U. Gastaldi, D. Parena, C. Cavion, Aldo Zenoni, G. Puddu, R. Garfagnini, S. Costa, Elena Botta, Michelangelo Agnello, S.N. Prakhov, Antonio Zoccoli, P. Cerello, A. Bertin, A. Lai, L. Musa, Antonio Ferretti, A. Filippi, R. Donà, A. Feliciello, Andrea Fontana, Mp Bussa, V.I. Tretyak, A. Maggiora, A. Saino, Stefania Vecchi, Marco Bruschi, L. Valacca, L. Venturelli, P.P. Temnikov, A. Vezzani, G. L. Usai, and S. Marcello
Subjects: Quantum chromodynamics, Rest (physics), Physics, Particle physics, Physics and Astronomy (miscellaneous), Glueball, Partial wave analysis, Pi, State (functional analysis), Engineering (miscellaneous), Pseudovector
Published: 2004

73. First results on nuclear physics with antineutrons by the OBELIX spectrometer

Author: M. Morando, Paolo Montagna, A. Grasso, S. De Castro, Felice Iazzi, L. Ferrero, A. Bertin, I. Massa, S. Marcello, Corrado Cicalo, S. Serci, U. Marconi, L. Vannucci, M. Lombardi, F. D'Isep, G. Maron, L. Busso, M. Corradini, G. Bendiscioli, N. Semprini Cesari, D. Galli, M.G. Sapozhnikov, L. Santi, Alberto Rotondi, L. Fava, R. Garfagnini, F. Nichitiu, S. Costa, M. Capponi, C. Guaraldo, Tullio Bressani, U. Gastaldi, G. L. Usai, V. Lucherini, A. Vitale, G. V. Margagliotti, V. Filippini, G. Pauli, R. A. Ricci, A. Maggiora, D. Panzieri, S. Tessaro, V.I. Tretyak, Aldo Zenoni, Mauro Villa, I. D'Antone, D. Calvo, Michelangelo Agnello, Guido Zavattini, Bruno Minetti, Antonio Zoccoli, P. Boccaccio, P. Gianotti, E. Lodi Rizzini, G. Piragino, A. Adamo, F. Balestra, G. Puddu, P.P. Temnikov, Gianfranco Zosi, Marco Bruschi, Alberto Masoni, E. Rossetto, L. Venturelli, F. Tosello, G. Bonazzola, A.M. Rozhdestvensky, Massimo Piccinini, Armando Lanaro, M. Poli, G. Vedovato, A. Feliciello, G. Belli, M.P. Bussa, Paola Salvini, A., Adamo, M., Agnello, F., Balestra, G., Belli, G., Bendiscioli, A., Bertin, P., Boccaccio, G. C., Bonazzola, T., Bressani, M., Bruschi, M. P., Bussa, L., Busso, D., Calvo, M., Capponi, C., Cicalò, M., Corradini, S., Costa, I., D'Antone, S., De Castro, F., D'Isep, L., Fava, A., Feliciello, L., Ferrero, V., Filippini, D., Galli, R., Garfagnini, U., Gastaldi, P., Gianotti, A., Grasso, C., Guaraldo, F., Iazzi, A., Lanaro, E., Lodi Rizzini, M., Lombardi, V., Lucherini, A., Maggiora, S., Marcello, U., Marconi, Margagliotti, Giacomo, G., Maron, A., Masoni, I., Massa, B., Minetti, M., Morando, P., Montagna, F., Nichitiu, D., Panzieri, G., Pauli, M., Piccinini, G., Piragino, M., Poli, G., Puddu, R. A., Ricci, E., Rossetto, A., Rotondi, A. M., Rozhdestvensky, P., Salvini, L., Santi, M. G., Sapozhnikov, N., Semprini Cesari, S., Serci, P., Temnikov, Tessaro, Susanna, F., Tosello, V. I., Tretyak, G. L., Usai, L., Vannucci, G., Vedovato, L., Venturelli, M., Villa, A., Vitale, G., Zavattini, A., Zenoni, A., Zoccoli, and G., Zosi
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Spectrometer, nbar-nucleus, Nuclear Theory, nbar-p, Antineutron, Nuclear physics, medicine.anatomical_structure, medicine, Nuclear Experiment, Spectroscopy, Nucleon, Nucleus
Abstract: First results on n annihilations on nucleons and nuclei measured by the OBELIX spectrometer are reported. Interesting new results on meson spectroscopy were obtained. Furthermore n-p and n - Nucleus (C, Al, Cu, Sn, Pb) annihilation cross sections between 100 and 300 MeV/c were measured.
Published: 1993

74. Semiconductor pixel detectors for digital mammography

Author: A. M. Stefanini, Maria Giuseppina Bisogni, G.-F. Dalla Betta, Valeria Rosso, L. Venturelli, Maria Evelina Fantacci, Maurizio Boscardin, M. Novelli, M. Quattrocchi, Pasquale Delogu, S. Zucca, and Salvator Roberto Amendolia
Subjects: Physics, Nuclear and High Energy Physics, Pixel, Physics::Instrumentation and Detectors, business.industry, Si pixel detectors, GaAs, Detector, Substrate (electronics), Medical imaging, Particle detector, Semiconductor detector, Gallium arsenide, chemistry.chemical_compound, Semiconductor, chemistry, Optoelectronics, business, Instrumentation, Diode
Abstract: We present some results obtained with silicon and gallium arsenide pixel detectors to be applied in the field of digital mammography. Even though GaAs is suitable for medical imaging applications thanks to its atomic number, which allows a very good detection efficiency, it often contains an high concentrations of traps which decrease the charge collection efficiency (CCE). So we have analysed both electrical and spectroscopic performance of different SI GaAs diodes as a function of concentrations of dopants in the substrate, in order to find a material by which we can obtain a CCE allowing the detection of all the photons that interact in the detector. Nevertheless to be able to detect low contrast details, efficiency and CCE are not the only parameters to be optimized; also the stability of the detection system is fundamental. In the past we have worked with Si pixel detectors; even if its atomic number does not allow a good detection efficiency at standard thickness, it has a very high stability. So keeping in mind the need to increase the Silicon detection efficiency we performed simulations to study the behaviour of the electrical potential in order to find a geometry to avoid the risk of electrical breakdown.
Published: 2003

75. Single and multinucleon antiproton–4He annihilation at rest

Author: Paola Salvini, V.G. Ableev, V.I. Tretyak, A. Maggiora, V. Lucherini, M. Bargiotti, Antonietta Donzella, D. Panzieri, Felice Iazzi, S. De Castro, Corrado Cicalo, G. Bendiscioli, Tullio Bressani, Umberto Marini Bettolo Marconi, M.P. Bussa, Germano Bonomi, L. Venturelli, A. Bertin, L. Ferrero, A. Feliciello, V. Filippini, R. Garfagnini, N. Mirfakhrai, Alberto Masoni, D. Galli, Marco Bruschi, Alberto Rotondi, C. Cavion, A.M. Rozhdestvensky, Aldo Zenoni, C. Petrascu, D. Calvo, G. Puddu, A. Panzarasa, M. Astrua, A. Grasso, S. Marcello, Mauro Villa, O.E. Gorchakov, F. Balestra, C. Guaraldo, Piergiorgio Cerello, A. Filippi, Massimo Piccinini, Roberto Spighi, Adriano Fontana, Antonio Zoccoli, Andrea Bianconi, G. L. Usai, A. Vitale, N. Semprini Cesari, Stefania Vecchi, Pietro Faccioli, Armando Lanaro, M. Capponi, V. Vagnoni, Elena Botta, Michelangelo Agnello, G. Vedovato, Paola Gianotti, A. De Falco, S. Serci, Benedetto Giacobbe, Paolo Montagna, L. Busso, Laura Fabbri, and O. Y. Denisov
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Branching fraction, Hadron, Nuclear physics, Pion, Antiproton, Physics::Accelerator Physics, Nuclear Experiment, Nucleon
Abstract: The p annihilation at rest in a NTP 4He-gas target has been studied by means of the Obelix spectrometer installed at the LEAR accelerator of CERN. Reactions with production of 2π−2π+, 2π−3π+, 2π−2π+p, 2π−π+2p, 2π−3p (with pπ>80 MeV/c and pp>300 MeV/c) have been selected and single- and multinucleon annihilations identified. For the first time some known mesonic and baryonic resonances have been observed in p 4He annihilations and branching ratios are evaluated for a number of reaction channels.
Published: 2002

76. Near-infrared laser spectroscopy of antiprotonic helium atoms

Author: Andreas Dax, H. Aghai-Khozani, Dezso Horvath, L. Venturelli, Y. Murakami, Ryugo S. Hayano, K. Todoroki, Masaki Hori, D. Barna, Hideaki Yamada, Nicola Zurlo, Takumi Kobayashi, and Anna Sótér
Subjects: Physics, QC1-999, chemistry.chemical_element, Atomic spectroscopy, Electron, Nanosecond, Laser, Charged particle, law.invention, Physics and Astronomy (all), chemistry, law, Physics in General, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Atomic physics, Spectroscopy, Nuclear Experiment, Antiprotonic helium, Helium
Abstract: The ASACUSA (Atomic Spectroscopy and Collisions Using Slow Antipro- tons) collaboration is currently attempting to observe a laser-induced resonant transition of antiprotonic helium atoms at wavelength of 1154.9 nm. Motivations to observe this transition and a nanosecond near-infrared laser prepared for this work are presented.
Published: 2014

77. Antiproton–to–electron mass ratio determined by two-photon laser spectroscopy of antiprotonic helium atoms

Author: Andreas Dax, Masaki Hori, S. Friedreich, D. Barna, L. Venturelli, Anna Sótér, T. Pask, Dezso Horvath, Eberhard Widmann, B. Juhász, Ryugo S. Hayano, and N. Zurlo
Subjects: Physics, Large Hadron Collider, QC1-999, Electron, Mass ratio, Nuclear physics, Physics and Astronomy (all), Two-photon excitation microscopy, Antiproton, Physics::Atomic Physics, Atomic physics, Spectroscopy, Antiprotonic helium
Abstract: The ASACUSA collaboration of CERN has recently carried out two-photon laser spectroscopy of antiprotonic helium atoms. Three transition frequencies were de- termined with fractional precisions of 2.3-5 parts in 10 9 . By comparing the results with three-body QED calculations, the antiproton-to-electron mass ratio was determined as 1836.1526736(23).
Published: 2014

78. The ATHENA experiment for the study of antihydrogen

Author: Germano Bonomi, Andrea Fontana, Alberto Rotondi, G. Testera, Nicola Zurlo, Claude Amsler, L. Venturelli, V. Lagomarsino, Alban Kellerbauer, and E. Lodi Rizzini
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Astronomy and Astrophysics, Penning trap, Atomic and Molecular Physics, and Optics, Nuclear physics, Antiproton Decelerator, Positron, Antiproton, Protonium, Antimatter, Physics::Atomic Physics, Antihydrogen
Abstract: In 2002, the ATHENA experiment was the first to produce large amounts of antihydrogen atoms at the CERN Antiproton Decelerator (AD). In this review article, we collect and discuss all the relevant results of the experiment: antiproton and positron cooling and their recombination dynamics in the nested Penning trap, the methods used to unambiguously identify the antiatoms as well as the protonium background, the dependence of the antihydrogen formation on mixing time and temperature. An attempt to interpret the results in terms of the two-body and three-body formation reactions, taking into account the complicated nested-trap dynamics, is also made. The relevance of the ATHENA results on future experiments is discussed, together with a short overview of the current antimatter physics at the AD.
Published: 2014

79. Enhancement of annihilation cross sections by electric interactions between the antineutron and the field of a large nucleus

Author: E. Lodi Rizzini, V. Mascagna, Andrea Bianconi, and L. Venturelli
Subjects: Physics, Nuclear and High Energy Physics, Annihilation, Nuclear Theory, FOS: Physical sciences, Antineutron, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, Polarization density, Dipole, High Energy Physics - Phenomenology (hep-ph), Antiproton, Electric field, Neutron, Vacuum polarization
Abstract: Data relative to antineutron and antiproton annihilation on large nuclei in the range 75-200 MeV/c present two unexpected features: (a) antineutron and antiproton cross sections have a similar size, (ii) the rise of the antineutron cross section at decreasing energy is much steeper than predictable for an inelastic process of purely strong nature at that energy. The observed behavior of antineutron-nucleus annihilations is similar to what would be expected for antiproton-nucleus annihilations, where Coulomb attraction focusses antiproton trajectories towards the nucleus, enhancing the inelastic cross section by a factor O(1/p) with respect to antineutrons on the same target. This results in a 1/p^2 behavior at small energies. The presence of a similar enhancement in the antineutron case may only be justified by an interaction with a longer range than strong interactions. Excluding a Coulomb force because of the antineutron neutrality, and taking into account that an intrinsic electric dipole is forbidden for the antineutron, the next choice is an electric dipole that is induced by the nuclear electric field. Recent theoretical works have shown that a non-negligible electric polarization may be induced in a neutron by QED vacuum polarization. Assuming this as a possibility, we have used a simple model to calculate the polarization strengths that are needed to fit the available data in terms of this effect. These are within the magnitude predicted by the vacuum polarization model. We have also discussed alternative scenarios that could induce an electric polarization of the antineutron as a consequence of the interplay between strong and e.m. interactions., Comment: 6 pages 2 figures
Published: 2014

80. A source of antihydrogen for in-flight hyperfine spectroscopy

Author: Hiroyuki A. Torii, Eberhard Widmann, Valerio Mascagna, H. Nagahama, M. Tajima, Johann Zmeskal, C. Sauerzopf, B. Radics, Chloé Malbrunot, A. Mohri, T. Mizutani, Yasuyuki Kanai, E. Lodi Rizzini, Hiroyuki Higaki, S. Sakurai, Yasuyuki Nagashima, K. Michishio, M. Leali, Y. Nagata, D. J. Murtagh, Yasuyuki Matsuda, Nicola Zurlo, B. Wu¨nschek, L. Venturelli, O. Massiczek, S. Van Gorp, M. Ohtsuka, Stefan Ulmer, Ken Suzuki, M. Diermaier, Naofumi Kuroda, S. Federmann, and Yasunori Yamazaki
Subjects: Genetics and Molecular Biology (all), Physics::General Physics, CPT symmetry, Physics beyond the Standard Model, General Physics and Astronomy, Biochemistry, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Standard Model, Nuclear physics, Physics and Astronomy (all), 0103 physical sciences, Nuclear Physics - Experiment, Physics::Atomic Physics, 010306 general physics, Spectroscopy, Antihydrogen, Hyperfine structure, Physics, Multidisciplinary, 010308 nuclear & particles physics, Chemistry (all), General Chemistry, Symmetry (physics), Antiproton, Biochemistry, Genetics and Molecular Biology (all), Particle Physics - Experiment
Abstract: Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart—hydrogen—is one of the most precisely investigated and best understood systems in physics research. High-resolution comparisons of both systems provide sensitive tests of CPT symmetry, which is the most fundamental symmetry in the Standard Model of elementary particle physics. Any measured difference would point to CPT violation and thus to new physics. Here we report the development of an antihydrogen source using a cusp trap for in-flight spectroscopy. A total of 80 antihydrogen atoms are unambiguously detected 2.7 m downstream of the production region, where perturbing residual magnetic fields are small. This is a major step towards precision spectroscopy of the ground-state hyperfine splitting of antihydrogen using Rabi-like beam spectroscopy., Comparing hydrogen and antihydrogen—its antimatter counterpart—provides important tests of fundamental symmetries in the Standard Model. Kuroda et al. present a source of antihydrogen atoms that may provide high-precision in-flight measurements of their ground-state hyperfine splitting.
Published: 2014

81. On the formation and decay of the atomcule

Author: F. Balestra, C. Petrascu, L. Santi, Antonietta Donzella, Armando Lanaro, M.P. Bussa, Germano Bonomi, C. Guaraldo, O. Y. Denisov, V. Lucherini, A.M. Rozhdestvensky, E. Lodi Rizzini, A. Grasso, M. Maggiora, Gianfranco Zosi, L. Busso, G. Piragino, G. V. Margagliotti, M.L. Colantoni, S.N. Prakhov, R. Vilar, M. Corradini, F. Tosello, S. Tessaro, L. Ferrero, G. Gomez, Andrea Bianconi, P. Gianotti, R. Garfagnini, L. Venturelli, V.I. Tretyak, A. Maggiora, and O.E. Gorchakov
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Microsecond, Large Hadron Collider, Metastability, Atomic physics, Nanosecond, Exotic atom, Bar (unit)
Abstract: Up to now it has been observed that a fraction of about 3% of the p 's stopped in a dense He target survives for a surprisingly long time (tens of microseconds). As suggested by Condo in 1964 the long lifetime of p 's in He is explained by the existence of metastable states of the exotic atom p He + . An analysis of data from p 's stopped in He targets at 3 bar pressure by the Obelix apparatus at the LEAR decelerator at CERN is presented. We do not observe any significative amount of “prompt” annihilations (few nanoseconds) after the p 's capture.
Published: 2001

82. Contribution from and waves in annihilation at rest

Author: G. Puddu, Sergio Serci, Michelangelo Agnello, N. Mirfakhrai, P. Montagna, M.P. Bussa, L. Ferrero, Stefania Vecchi, Alberto Rotondi, E. Lodi Rizzini, C. Petrascu, Andrea Bianconi, A.E. Kudryavtsev, G. L. Usai, I. Massa, S. Marcello, Felice Iazzi, A. Masoni, A. Bertin, M. Poli, S. De Castro, A. Filippi, Corrado Cicalo, R. Donà, Germano Bonomi, S.N. Prakhov, A. Feliciello, R. Spighi, Paola Gianotti, D. D'Isep, Marco Bruschi, Mauro Villa, Armando Lanaro, D. Panzieri, L. Venturelli, F. Tosello, Adriano Fontana, V. Filippini, D. Galli, S. Tessaro, B. Giacobbe, A. Grasso, A.M. Rozhdestvensky, V.I. Tretyak, Vincenzo Vagnoni, V. Lucherini, Maurizio Piccinini, Aldo Zenoni, S. Costa, U. Marconi, A. Vitale, Elena Botta, Paola Salvini, A. Maggiora, O.E. Gorchakov, F. Balestra, A. De Falco, G. Bendiscioli, O.Yu. Denisov, Bruno Minetti, C. Guaraldo, A. Panzarasa, L. Busso, Piergiorgio Cerello, M. Capponi, Tullio Bressani, D. Calvo, N. Semprini Cesari, and Antonio Zoccoli
Subjects: Nuclear physics, Physics, Nuclear reaction, Nuclear and High Energy Physics, Annihilation, Protonium, Branching fraction, Excited state, Hadron, Atomic physics, Exotic atom
Abstract: The annihilation frequencies of 19 p p annihilation reactions at rest obtained in different target densities are analysed in order to determine the values of the P -wave annihilation percentage at each target density and the average hadronic branching ratios from P - and S -states. Both the assumptions of linear dependence of the annihilation frequencies on the P -wave annihilation percentage of the protonium state and the approach with the enhancement factors of Batty are considered. Furthermore the cases of incompatible measurements are discussed.
Published: 2001

83. [Untitled]

Author: C. Lenz Cesar, M. J. T. Collier, Niels Madsen, G. Testera, G. Rouleau, R. Landua, C. Carraro, V. Filippini, M. C. Fujiwara, R. Funakoshi, P. Genova, P. Riedler, Michael H. Holzscheiter, Michael Doser, Claude Amsler, G. Manuzio, G. Bendiscioli, Alessandro Variola, T. Yamazaki, J. S. Hangst, W. Joffrain, P. D. Bowe, Alberto Rotondi, H. Pruys, Germano Bonomi, M. Macri, P. Montagna, D. P. van der Werf, L. Venturelli, L. V. Jørgensen, M. Marchesotti, Adriano Fontana, M. Amoretti, K.S. Fine, E. Lodi-Rizzini, Ryugo S. Hayano, Hiroyuki Higaki, V. Lagomarsino, C. Regenfus, D. Lindelöf, A. Bouchta, T. L. Watson, Yasunori Yamazaki, D. Grögler, Paola Salvini, and M. Charlton
Subjects: Physics, Physics::General Physics, Nuclear and High Energy Physics, Large Hadron Collider, CPT symmetry, Condensed Matter Physics, Penning trap, Atomic and Molecular Physics, and Optics, Antiproton Decelerator, Nuclear physics, Positron, Antiproton, Physics::Atomic and Molecular Clusters, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics, Physical and Theoretical Chemistry, Antihydrogen
Abstract: The ATHENA experiment at the Antiproton Decelerator facility at CERN aims at testing CPT symmetry with antihydrogen. An overview of the experiment, together with preliminary results of development towards the production of slow antihydrogen are reported.
Published: 2001

84. Experimental evidence of antiproton reflection by a solid surface

Author: R. Donà, A. Cristiano, E. Lodi Rizzini, L. Venturelli, M. Corradini, Andrea Bianconi, M. Leali, N. Zurlo, A. Bianconi, M. Corradini, A. Cristiano, M. Leali, E. Lodi Rizzini, L. Venturelli, N. Zurlo, and R. Donà
Subjects: Physics, Range (particle radiation), Annihilation, Scattering, Monte Carlo method, FOS: Physical sciences, Antiprotons · Surfaces · Coulombic interaction, Atomic and Molecular Physics, and Optics, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Reflection (mathematics), Antiproton, Antimatter, Atomic physics, Energy (signal processing)
Abstract: We report here experimental evidence of the reflection of a large fraction of a beam of low energy antiprotons by an aluminum wall. This derives from the analysis of a set of annihilations of antiprotons that come to rest in rarefied helium gas after hitting the end wall of the apparatus. A Monte Carlo simulation of the antiproton path in aluminum indicates that the observed reflection occurs primarily via a multiple Rutherford-style scattering on Al nuclei, at least in the energy range 1-10 keV where the phenomenon is most visible in the analyzed data. These results contradict the common belief according to which the interactions between matter and antimatter are dominated by the reciprocally destructive phenomenon of annihilation., 5 pages with 5 figures
Published: 2008

85. Observation of the 1154.9 nm transition of antiprotonic helium

Author: Andreas Dax, K. Todoroki, Hossein Aghai-Khozani, Hiroyuki Yamada, Ryugo S. Hayano, Dezso Horvath, D. Barna, Masaki Hori, Nicola Zurlo, Anna Sótér, Takumi Kobayashi, L. Venturelli, and Y. Murakami
Subjects: Physics, education.field_of_study, Population, chemistry.chemical_element, Resonance, Condensed Matter Physics, Quantum number, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, chemistry, 0103 physical sciences, Principal quantum number, Radiative transfer, Nuclear Physics - Experiment, Atomic physics, 010306 general physics, education, Spectroscopy, Antiprotonic helium, Helium
Abstract: The resonance transition $(n,l)=(40,36)\to(41,35)$ of the antiprotonic helium ($\overline{\mathrm{p}}^{4}$He$^{+}$) isotope at a wavelength of 1154.9 nm was detected by laser spectroscopy. The population of $\overline{\mathrm{p}}^{4}$He$^{+}$ occupying the resonance parent state $(40,36)$ was found to decay at a rate of $0.45\pm0.04$ $\mu$s$^{-1}$, which agreed with the theoretical radiative rate of this state. This implied that very few long-lived $\overline{\mathrm{p}}^{4}$He$^{+}$ are formed in the higher-lying states with principal quantum number $n\ge41$, in agreement with the results of previous experiments.
Published: 2013

86. Antiproton–neon annihilation at 57 MeV/c

Author: A. Grasso, M.P. Bussa, Andrea Ferrero, Germano Bonomi, L. Ferrero, C. Guaraldo, E. Lodi Rizzini, L. Venturelli, F. Tosello, M. Maggiora, Andrea Bianconi, Aldo Zenoni, M.L. Colantoni, G. Piragino, A. Maggiora, G.B. Pontecorvo, F. Balestra, and L. Busso
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Neon, Momentum (technical analysis), Cross section (physics), Annihilation, chemistry, Physics::Instrumentation and Detectors, Antiproton, chemistry.chemical_element, Atomic physics
Abstract: The p Ne annihilation cross section is measured for the first time in the momentum interval (53÷63) MeV/c. About 9000 pictures collected by the Streamer Chamber Collaboration (PS179) at LEAR-CERN have been scanned. Four events are found, corresponding to σ ann =2210±1105 mb. The result is compared to the set of measurements presently available in the region of low p momentum.
Published: 2000

87. Antiproton–helium 3 annihilation at 55 MeV/c

Author: F. Tosello, M.P. Bussa, Germano Bonomi, L. Busso, L. Ferrero, F. Balestra, A. Maggiora, Andrea Ferrero, A. Grasso, G. Piragino, E. Lodi Rizzini, G.B. Pontecorvo, L. Venturelli, M.L. Colantoni, Aldo Zenoni, Andrea Bianconi, C. Guaraldo, and M. Maggiora
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Momentum (technical analysis), Cross section (physics), Annihilation, Antiproton, Helium-3, Atomic physics
Abstract: The p 3He annihilation cross section is measured for the first time in the momentum interval (50÷60) MeV/c. About 9000 pictures collected by the Streamer Chamber Collaboration (PS179) at LEAR–CERN have been scanned. Six events are found, corresponding to σann=1850±700 mb. The result is compared to the set of measurements presently available in the region of low p momentum.
Published: 2000

88. Study of η and η′ production in annihilations

Author: Alberto Masoni, D. Calvo, A. Grasso, A.M. Rozhdestvensky, A. Filippi, O.E. Gorchakov, M. Capponi, Tullio Bressani, R. Donà, Germano Bonomi, Maurizio Piccinini, R. Spighi, S. Mauro, S. De Castro, Piergiorgio Cerello, C. Guaraldo, M. Poli, Michelangelo Agnello, S. Serci, Stefania Vecchi, Paolo Montagna, D. Panzieri, Bruno Minetti, Mauro Villa, M.G. Sapozhnikov, V. Filippini, Paola Salvini, E. Lodi Rizzini, V. Vagnoni, V.I. Tretyak, A. Maggiora, S.N. Prakhov, V. Lucherini, Aldo Zenoni, V.G. Ableev, G. Puddu, G. Bendiscioli, N. Semprini Cesari, F. Balestra, L. Venturelli, Maria Pia Bussa, L. Busso, U. Marconi, R. Garfagnini, B. Giacobbe, Antonio Zoccoli, S. Costa, Elena Botta, Marco Bruschi, A. Feliciello, A. Panzarasa, O. Y. Denisov, L. Vannucci, Andrea Bianconi, G. L. Usai, I. Massa, S. Marcello, F. D'Isep, Armando Lanaro, A. Vitale, G. Vedovato, Paola Gianotti, A. Bertin, D. Galli, Adriano Fontana, N. Mirfakhraee, F. Tosello, S. Tessaro, Felice Iazzi, Corrado Cicalo, Alberto Rotondi, and C. Petrascu
Subjects: Quark, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, P wave, Pseudoscalar meson, Nuclear physics, Pseudoscalar, Production (computer science), Mixing (physics), Line (formation)
Abstract: The annihilation fractions and cross sections for the n p annihilation reaction in flight (∼50–400 MeV/c) into ηπ+ and η′π+ final states have been measured. The first ones follow the trend expected for P wave annihilations. From the ratios of the yields an evaluation of the pseudoscalar mixing angle in the standard form is possible. The value found shows that for pseudoscalar meson production from P wave the Quark Line Rule is not grossly violated.
Published: 1999

89. and annihilation cross sections at very low energy

Author: N. Semprini Cesari, D. Galli, Andrea Bianconi, G. L. Usai, M.P. Bussa, Piergiorgio Cerello, S. Costa, G. Bendiscioli, Paola Salvini, Stefania Vecchi, R. A. Ricci, S.N. Prakhov, Adriano Fontana, I. Massa, N. Mirfakhrai, S. Marcello, L. Ferrero, L. Venturelli, C. Guaraldo, Maurizio Piccinini, R. Garfagnini, R. Spighi, F. D'Isep, Alberto Rotondi, Armando Lanaro, U. Marconi, M. Corradini, M. Capponi, A. Panzarasa, C. Petrascu, F. Tosello, S. Tessaro, G. Puddu, Tullio Bressani, A. Grasso, S. De Castro, A. Vitale, Elena Botta, U. Gastaldi, Antonio Zoccoli, S. Mauro, V.I. Tretyak, Alberto Masoni, S. Serci, M. Poli, Antonietta Donzella, A. Feliciello, V. Lucherini, D. Calvo, B. Giacobbe, Mauro Villa, V. Vagnoni, Paola Gianotti, Felice Iazzi, Corrado Cicalo, O.E. Gorchakov, Germano Bonomi, D. Panzieri, Michelangelo Agnello, A.M. Rozhdestvensky, A. Filippi, R. Donà, E. Lodi Rizzini, Aldo Zenoni, A. Bertin, Bruno Minetti, Marco Bruschi, F. Balestra, L. Vannucci, O. Y. Denisov, Paolo Montagna, and L. Busso
Subjects: Nuclear physics, Momentum, Physics, Nuclear and High Energy Physics, Cross section (physics), Low energy, Annihilation, Deuterium, Nuclear Experiment
Abstract: The p D and p 4 He total annihilation cross sections have been measured with the Obelix apparatus at LEAR at, respectively, three and two values of the p incident momentum between 70 MeV/c and 36 MeV/c. The values of the p D annihilation cross section, at such low energies, are in agreement with a surprising result obtained in a recent low statistics measurement of the antiprotonic deuterium K α X-rays [M. Augsburger et al., Phys. Lett. B 461 (1999) 417] (see following article), concerning the unexpected narrow width of the antiprotonic deuterium 1s level.
Published: 1999

90. Evidence for two pseudoscalar states in the 1.4–1.5 GeV mass region

Author: R. Spighi, A. Masoni, Germano Bonomi, L. Venturelli, V.I. Tretyak, V. Lucherini, D. Galli, A. Filippi, Bruno Minetti, A. Feliciello, Petar Temnikov, Antonio Zoccoli, D. D'Isep, M. Capponi, Tullio Bressani, R. Garfagnini, A. Grasso, S. Costa, A. Maggiora, M. Lombardi, L. Ferrero, O.E. Gorchakov, Elena Botta, A. De Falco, F. Tosello, S. Tessaro, Michelangelo Agnello, I. Massa, Mauro Villa, S.N. Prakhov, A. Panzarasa, S. Marcello, R. Donà, Sergio Serci, Alberto Rotondi, V. Filippini, F. Balestra, G. Vedovato, B. Giacobbe, U. Marconi, Vincenzo Vagnoni, C. Petrascu, Felice Iazzi, M. Bruschi, V.G. Ableev, D. Panzieri, Piergiorgio Cerello, A. Vitale, Aldo Zenoni, Stefania Vecchi, Adriano Fontana, M. Poli, Corrado Cicalo, G. Puddu, M. Piccinini, D. Calvo, C. Guaraldo, P. Montagna, N. Semprini Cesari, Paola Gianotti, Andrea Bianconi, G. L. Usai, S. Mauro, E. Lodi Rizzini, Paola Salvini, A.M. Rozhdestvensky, N. Mirfakhrai, Armando Lanaro, S. De Castro, O. Y. Denisov, L. Busso, and A. Bertin
Subjects: Pseudoscalar, Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics
Abstract: A confirming evidence for two pseudoscalar states with masses M 1 =1405±5, Γ 1 =50±4 MeV/ c 2 and M 2 =1500±10, Γ 2 =100±20 MeV/ c 2 is reported. The second pseudoscalar fills the nonet and leaves the first as an outsider supporting the hypothesis for its exotic nature.
Published: 1999

91. Light baryon production in binary annihilation reactions at rest

Author: L. Fava, M. Capponi, Tullio Bressani, S. De Castro, U. Gastaldi, A.M. Rozhdestvensky, V. Filippini, N. Mirfakhraee, D. Galli, G. Puddu, F. Tosello, M.G. Sapozhnikov, S. Tessaro, N. Semprini Cesari, Paolo Montagna, C. Cavion, L. Santi, F. Nichitiu, Aldo Zenoni, E. Lodi Rizzini, P. Cerello, A. Panzarasa, Petar Temnikov, R. Spighi, A. Bertin, V.G. Ableev, A. Masoni, Armando Lanaro, O. Gortchakov, S. Costa, D. Calvo, G. Pauli, Antonio Zoccoli, A. Grasso, F. Vigotti, M.P. Bussa, Vincenzo Vagnoni, G. Vedovato, Stefania Vecchi, G. Maron, Elena Botta, U. Marconi, A. Filippi, Paola Gianotti, Bruno Minetti, R. Donà, V. Alberico, M. Corradini, Sergio Serci, Michelangelo Agnello, Felice Iazzi, Corrado Cicalo, S. Mauro, M. Lombardi, S.N. Prakhov, G. Piragino, A. Vitale, Andrea Bianconi, G. L. Usai, Gianfranco Zosi, M. Poli, D. Panzieri, D. D'Isep, I. D'Antone, Mauro Villa, O. Y. Denisov, Adriano Fontana, Maurizio Piccinini, A. Ferretti, R. Garfagnini, B. Giacobbe, L. Busso, S. Marcello, Paola Salvini, V.I. Tretyak, A. Maggiora, V. Lucherini, Marco Bruschi, L. Venturelli, F. Balestra, L. Ferrero, Alberto Rotondi, C. Petrascu, L. Vannucci, C. Guaraldo, Alessandro Feliciello, and G. Bendiscioli
Subjects: Baryon, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Deuterium, Antiproton, Binary number
Abstract: We report the study of light baryon production in two-prong annihilation reactions due to antiprotons stopping in gaseous deuterium and detected by the OBELIX spectrometer (LEAR, CERN). A clear signal of the Δ(1232) production in binary reactions was found in both annihilation channels: p d→π − Δ + (Δ + →π 0 p) and p d→π 0 Δ 0 (Δ 0 →π − p) . The annihilation probabilities for these reactions turned out to be Y=(1.01±0.08)×10−5 and Y=(1.12±0.20)×10−5, respectively. In addition, the annihilation probability for the prototype Pontecorvo reaction p d→π − p was measured with the best world statistics: Y=(1.46±0.08)×10−5.
Published: 1999

92. Study of and annihilation reactions in flight

Author: D. Panzieri, E. Lodi Rizzini, Alberto Masoni, G. Vedovato, D. Calvo, N. Semprini Cesari, Paolo Montagna, Paola Gianotti, V. Filippini, L. Santi, G. Bendiscioli, Antonietta Donzella, C. Cavion, Aldo Zenoni, A.M. Rozhdestvensky, Michelangelo Agnello, B. Giacobbe, C. Guaraldo, O. Y. Denisov, C. Fanara, S. Costa, S.N. Prakhov, R. Spighi, M. Lombardi, V. Vagnoni, A. Grasso, L. Valacca, O.E. Gorchakov, A. Raimondo, L. Venturelli, M.G. Sapozhnikov, M. Corradini, V. Alberico, F. Nichitiu, M. Capponi, L. Busso, G. Pauli, A. Panzarasa, Tullio Bressani, U. Gastaldi, V.G. Ableev, F. Balestra, S. De Castro, M.P. Bussa, Stefania Vecchi, Piergiorgio Cerello, M. Poli, Armando Lanaro, A. Feliciello, S. Serci, U. Marconi, V.I. Tretyak, G. Maron, A. Maggiora, Paola Salvini, A. Vitale, V. Lucherini, S. Mauro, D. Bergo, Bruno Minetti, F. Vigotti, L. Vannucci, Antonio Zoccoli, Mauro Villa, Elena Botta, S. Marcello, Marco Bruschi, R. Garfagnini, G. L. Usai, L. Ferrero, Alberto Rotondi, C. Petrascu, D. Galli, Maurizio Piccinini, Gianfranco Zosi, Adriano Fontana, A. Ferretti, N. Mirfakhraee, F. Tosello, S. Tessaro, C. Scoglio, Felice Iazzi, Corrado Cicalo, A. Filippi, R. Donà, Petar Temnikov, A. Bertin, and G. Puddu
Subjects: Physics, Nuclear physics, Nuclear reaction, Nuclear and High Energy Physics, Annihilation, Pion, Meson, OZI rule, Nuclear Theory, Nuclear Experiment, Nucleon, Antineutron, Quarkonium
Abstract: The results of a study of the annihilation reactions n p → θπ + and n p → ωπ + are reported; the data were collected by the OBELIX apparatus, with antineutrons annihilating in flight (momenta from ∼ 50 MeV/ c to 405 MeV/ c ). Annihilation frequencies and annihilation cross sections have been deduced, for both channels, as a function of antineutron momentum. From the cross section ratio, a substantial deviation from OZI rule expectations is observed. An s s quark content in the nucleon offers a fairly plausible explanation for such an effect.
Published: 1999

93. Study of φ and f′2(1525) meson production in annihilation at rest

Author: M. Capponi, Tullio Bressani, U. Gastaldi, A. Feliciello, S. Mauro, Paola Salvini, Armando Lanaro, V. Vagnoni, L. Valacca, D. D'Isep, L. Fava, G. Puddu, M. Poli, L. Venturelli, G. Vedovato, Paola Gianotti, U. Marconi, A. Filippi, A.M. Rozhdestvensky, C. Scoglio, S. De Castro, R. Donà, D. Galli, S. Costa, A. Vitale, Alberto Masoni, S.N. Prakhov, L. Ferrero, R. Spighi, S. Serci, D. Calvo, M. Corradini, F. Nichitiu, Alberto Rotondi, C. Petrascu, V.P. Nomokonov, B. Giacobbe, O.E. Gorchakov, N. Semprini Cesari, A M Rosca, D. Panzieri, N. Mirfakhrai, G. Pauli, A. Panzarasa, S. Marcello, L. Santi, V. Filippini, Maurizio Piccinini, Marco Bruschi, Antonio Zoccoli, Elena Botta, Piergiorgio Cerello, C. Cavion, V.I. Tretyak, Michelangelo Agnello, M.P. Bussa, A. Maggiora, V. Lucherini, Aldo Zenoni, L. Busso, Stefania Vecchi, L. Vannucci, Petar Temnikov, Mauro Villa, A. Bertin, F. Tosello, S. Tessaro, A Alberico, E. Lodi Rizzini, R. Bianconi, R. Garfagnini, A. Grasso, Felice Iazzi, Corrado Cicalo, F. Vigotti, G. L. Usai, F. Balestra, Adriano Fontana, A. Ferretti, Paolo Montagna, C. Guaraldo, Bruno Minetti, G. Bendiscioli, O.Yu. Denisov, M. Lombardi, M.G. Sapozhnikov, V.G. Ableev, and G. Maron
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, OZI rule, Branching fraction, Antiproton, Yield (chemistry), Mass spectrum, Dalitz plot, Quantum number
Abstract: The reaction p p→K + K − π 0 was analysed for antiproton annihilations at rest at three hydrogen target densities. A strong dependence of the p p→φπ 0 yield on the quantum numbers of the initial state is observed. The branching ratio of the φπ0 channel from the 3S1 initial state is more than 15 times larger than the one from the 1P1 state. A large apparent violation of the OZI rule for tensor meson production from p p -annihilations from the P-waves (1+++2++) is observed: Rexp(f′2π0/f2π0)=(149±20)·10−3, significantly exceeding the OZI-rule prediction R=16·10−3.
Published: 1998

94. Study of the isovector scalar mesons in the channel p̄p→K±K0Sπ∓ at rest with initial angular momentum state selection

Author: V. Filippini, N. Semprini Cesari, L. Santi, Antonietta Donzella, C. Scoglio, C. Cavion, Aldo Zenoni, A. Masoni, Felice Iazzi, Gianfranco Zosi, Tullio Bressani, U. Gastaldi, S. Mauro, Armando Lanaro, G. Bendiscioli, Adriano Fontana, Piergiorgio Cerello, G. Pauli, F. Vigotti, M. Poli, Corrado Cicalo, M. Capponi, A. Saino, S. Costa, Elena Botta, O. Y. Denisov, G. Vedovato, D. Calvo, Petar Temnikov, R. A. Ricci, Paola Gianotti, M. Corradini, Michelangelo Agnello, A. Bertin, S.N. Prakhov, F. Tosello, S. Tessaro, Paolo Montagna, A. Grasso, A. Feliciello, C. Guaraldo, Antonio Ferretti, L. Ferrero, A.M. Rozhdestvensky, F. Balestra, Benedetto Giacobbe, Roberto Spighi, G. Puddu, Paola Salvini, Massimo Piccinini, A. Benedettini, M. Lombardi, G. L. Usai, R. Garfagnini, Umberto Marini Bettolo Marconi, E. Lodi Rizzini, Alberto Rotondi, C. Petrascu, G. Maron, D. D'Isep, D. Galli, S. Marcello, V.I. Tretyak, R. Donà, Bruno Minetti, S. De Castro, A. Filippi, L. Busso, E. Rossetto, M.G. Sapozhnikov, M.P. Bussa, Stefania Vecchi, V. Lucherini, V.G. Ableev, D. Panzieri, Mauro Villa, L. Valacca, L. Venturelli, Sergio Serci, A. Vitale, A. Maggiora, O.E. Gorchakov, Marco Bruschi, A M Rosca, V. Vagnoni, F. Nichitiu, and Antonio Zoccoli
Subjects: Hydrogen density, Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Angular momentum, Isovector, Meson, Scalar (physics)
Abstract: The study of the I =1, J PC =0 ++ states with the OBELIX detector in the channel p p→K ± K 0 S π ∓ at three different target densities is reported. The data show the evidence for an extra scalar state with mass 1.29±0.01 GeV/ c 2 and width 0.080±0.005 GeV/ c 2 .
Published: 1998

95. Study of thef0(1500)/f2(1565)production in the exclusive annihilationn̄p→π+π+π−in flight

Author: Roberto Spighi, Antonietta Donzella, V.G. Ableev, Bruno Minetti, O. Gortchakov, A. Vitale, V.I. Tretyak, A. Collamati, Paola Salvini, A. Maggiora, N. Mirfakhrai, V. Lucherini, D. Bergo, L. Busso, S.N. Prakhov, E. Rossetto, L. Fava, P.P. Temnikov, M. Poli, A. Grasso, S. De Castro, M. Lombardi, M. Corradini, Alberto Masoni, Marco Bruschi, F. Nichitiu, G. Bendiscioli, D. Galli, G. Vedovato, G. Pauli, C. Scoglio, S. Serci, L. Valacca, D. Calvo, L. Venturelli, C. Guaraldo, Adriano Fontana, A M Rosca, Mauro Villa, Benedetto Giacobbe, A. Vezzani, D. Panzieri, M. Capponi, Paolo Montagna, Paola Gianotti, F. Tosello, C. Fanara, E. Lodi Rizzini, Umberto Marini Bettolo Marconi, M.P. Bussa, Alessandro Feliciello, S. Tessaro, Michelangelo Agnello, V. Filippini, Stefania Vecchi, C. Cavion, Aldo Zenoni, A.M. Rozhdestvensky, Antonio Ferretti, Massimo Piccinini, Felice Iazzi, Corrado Cicalo, G. Maron, Armando Lanaro, A. Saino, O. Y. Denisov, S. Marcello, S. Costa, F. D'Isep, G. L. Usai, F. Balestra, Tullio Bressani, U. Gastaldi, G. Puddu, L. Ferrero, Alberto Rotondi, C. Petrascu, N. Semprini Cesari, L. Vannucci, L. Santi, Elena Botta, F. Vigotti, R. Garfagnini, P. Cerello, A. Bertin, P. Damiani, A. Filippi, R. Donà, Antonio Zoccoli, and M.G. Sapozhnikov
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Pi, Invariant mass, Production (computer science)
Abstract: The spin-parity analysis of the $\mathrm{n\ifmmode \bar{}\else \={}\fi{}}\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ exclusive reaction in flight is presented. The main aim is to study the $({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$ invariant mass spectrum in the region around 1500 MeV. The analysis was performed with a Breit-Wigner parametrization for all the resonant states and, for the scalar sector in the mass region below 1.2 GeV, by means of a K-matrix-like treatment. It clearly shows the need for two states, a scalar one ${(0}^{++})$ with mass and width $(1522\ifmmode\pm\else\textpm\fi{}25) \mathrm{MeV}$ and $(108\ifmmode\pm\else\textpm\fi{}33) \mathrm{MeV}$, and a tensorial one ${(2}^{++})$ with mass $(1575\ifmmode\pm\else\textpm\fi{}18) \mathrm{MeV}$ and width $(119\ifmmode\pm\else\textpm\fi{}24) \mathrm{MeV}$, respectively. In addition, the analysis requires the presence of a scalar state at $(1280\ifmmode\pm\else\textpm\fi{}55) \mathrm{MeV}$, $(323\ifmmode\pm\else\textpm\fi{}13) \mathrm{MeV}$ broad, and of a second vectorial one, in addition to the ${\ensuremath{\rho}}^{0}(770)$ signal, with mass and width $(1348\ifmmode\pm\else\textpm\fi{}33) \mathrm{MeV}$ and $(275\ifmmode\pm\else\textpm\fi{}10) \mathrm{MeV}$, respectively.
Published: 1998

96. HERA-G, A NEW EXPERIMENT FOR GLUEBALL, HYBRID AND ODDERON STUDIES AT DESY. PROPOSAL FOR A NEW EXPERIMENTAL PROGRAM USING THE EXISTING HERA-B DETECTOR

Author: T. Lohse, M. zur Nedden, M. Bruschi, M. Capponi, B. Giacobbe, U. Marconi, M. Poli, R. Spighi, S. Vecchi, A. Bianconi, M. Corradini, A. Donzella, E. Lodi Rizzini, L. Venturelli, N. Zurlo, Y.u. Kiryushin, A. Lanyov, D. Pose, S. Reznikov, S. Somov, G. Evgrafov, I. Belotelov, M. A. Reyes, J. Felix, M. Medinnis, M. Brauer, J. Spengler, V. Pugatch, Y.u. Vasilev, V. Aushev, S. Prystupa, Y.u. Pavlenko, V. Kyva, M. Molodyko, J. D. Hansen, R. Muresan, M. Staric, R. Pestotnik, A. Stanovnik, S. Erhan, P. Schlein, G. Medin, V. A. Bogatyrev, V. Balagura, M. Danilov, F. Khasanov, B. Fominykh, R. Mizuk, I. Matchikhilian, I. Rostovtseva, V. Popov, S. Esenov, S. Shuvalov, I. Tikhomirov, Y.u. Zaitsev, S. Aplin, V. Galkin, A. Golovin, D. Ryzhikov, V. Savelev, M. Zaboudko, Y. Arestov, B. Chuiko, D. Konstantinov, V. Lishin, V. Shelikhov, L. Ferrero, R. Garfagnini, G. Piragino, BARGIOTTI, MARIANNE, BERTIN, ANTONIO, CARBONE, ANGELO, DE CASTRO, STEFANO, FABBRI, LAURA, FACCIOLI, PIETRO, GALLI, DOMENICO, MASSA, IGNAZIO GIACOMO, PICCININI, MAURIZIO, SEMPRINI CESARI, NICOLA, VILLA, MAURO, VITALE, ANTONIO, ZOCCOLI, ANTONIO, T. Lohse, M. zur Nedden, M. Bargiotti, A. Bertin, M. Bruschi, M. Capponi, A. Carbone, S. De Castro, L. Fabbri, P. Faccioli, D. Galli, B. Giacobbe, U. Marconi, I. Massa, M. Piccinini, M. Poli, N. Semprini-Cesari, R. Spighi, S. Vecchi, M. Villa, A. Vitale, A. Zoccoli, A. Bianconi, M. Corradini, A. Donzella, E. Lodi Rizzini, L. Venturelli, N. Zurlo, Yu. Kiryushin, A. Lanyov, D. Pose, S. Reznikov, S. Somov, G. Evgrafov, I. Belotelov, M.A. Reye, J. Felix, M. Medinni, M. Brauer, J. Spengler, V. Pugatch, Yu. Vasilev, V. Aushev, S. Prystupa, Yu. Pavlenko, V. Kyva, M. Molodyko, J.D. Hansen, R. Muresan, M. Staric, R. Pestotnik, A. Stanovnik, S. Erhan, P. Schlein, G. Medin, V.A. Bogatyrev, V. Balagura, M. Danilov, F. Khasanov, B. Fominykh, R. Mizuk, I. Matchikhilian, I. Rostovtseva, V. Popov, S. Esenov, S. Shuvalov, I. Tikhomirov, Yu. Zaitsev, S. Aplin, V. Galkin, A. Golovin, D. Ryzhikov, V. Savelev, M. Zaboudko, Y. Arestov, B. Chuiko, D. Konstantinov, V. Lishin, V. Shelikhov, L. Ferrero, R. Garfagnini, and G. Piragino
Published: 2004

97. Dynamical selection rules from p anti-p annihilation at rest in three meson final states

Author: G. Puddu, Paolo Montagna, R. Garfagnini, P. Cerello, Antonio Zoccoli, V. Filippini, M. Corradini, A. Bertin, F. Nichitiu, L. Venturelli, C. Guaraldo, E. Lodi Rizzini, Michelangelo Agnello, Armando Lanaro, Elena Botta, G. Pauli, Felice Iazzi, C. Cavion, S.N. Prakhov, Aldo Zenoni, M. Astrua, A. Saino, G. L. Usai, L. Ferrero, Andrea Fontana, G. Vedovato, L. Fava, S. Marcello, L. Vannucci, Alberto Andrighetto, A. Grasso, V.I. Tretyak, O. Y. Denisov, Alberto Rotondi, Mauro Villa, A. Maggiora, S. De Castro, Antonietta Donzella, Roberto Spighi, M. Lombardi, C. Petrascu, F. D'Isep, D. Parena, Benedetto Giacobbe, Antonio Ferretti, F. Tosello, A. Feliciello, A. Filippi, A. Vezzani, Bruno Minetti, L. Busso, D. Galli, M. Morando, S. Serci, A.M. Rozhdestvensky, E. Rossetto, M.G. Sapozhnikov, A. Vitale, N. Mirfakhraee, Umberto Marini Bettolo Marconi, S. Tessaro, P.P. Temnikov, Massimo Piccinini, Paola Salvini, I. D'Antone, Marco Bruschi, M.P. Bussa, R. A. Ricci, M. Capponi, Stefania Vecchi, V.G. Ableev, D. Panzieri, O.E. Gorchakov, A M Rosca, Alberto Masoni, D. Calvo, V. Lucherini, G. Bendiscioli, F. Balestra, C. Cicalo, N. Semprini Cesari, L. Santi, S. Costa, P. Gianotti, Tullio Bressani, U. Gastaldi, M. BARGIOTTI, A. BERTIN, M. BRUSCHI, M. CAPPONI, A. CARBONE, S. DE CASTRO, R. DONÀ, L. FABBRI, P. FACCIOLI, D. GALLI, B. GIACOBBE, F. GRIMALDI, U. MARCONI, I. MASSA, M. PICCININI, N. SEMPRINI CESARI, R. SPIGHI, S. VECCHI, M. VILLA, A. VITALE, A. ZOCCOLI, M. POLI, A. BIANCONI, M.P. BUSSA, M. CORRADINI, A. DONZELLA, E. LODI RIZZINI, L. VENTURELLI, C. CICALÒ, A. DE FALCO, A. MASONI, G. PUDDU, S. SERCI, G. USAI, O.E. GORCHAKOV, S.N. PRAKHOV, A.M. ROZHDESTVENSKY, M.G. SAPOZHNIKOV, V.I. TRETYAK, P. GIANOTTI, C. GUARALDO, A. LANARO, V. LUCHERINI, C. PETRASCU, R. A. RICCI, V. FILIPPINI, A. FONTANA, P. MONTAGNA, A. PANZARASA, A. ROTONDI, P. SALVINI, A. ZENONI, F. BALESTRA, L. BUSSO, P. CERELLO, O. DENISOV, L. FERRERO, R. GARFAGNINI, A. MAGGIORA, D. PANZIERI, F. TOSELLO, E. BOTTA, T. BRESSANI, D. CALVO, F. DE MORI, A. FELICIELLO, A. FILIPPI, N. MIRFAKHRAI, S. MARCELLO, M. AGNELLO, and F. IAZZI
Subjects: Physics, Annihilation, Physics and Astronomy (miscellaneous), Meson, Hydrogen, Hadron, chemistry.chemical_element, Coincidence, chemistry, Protonium, Isospin, Production (computer science), Atomic physics, Engineering (miscellaneous)
Abstract: The hadronic annihilation branching-ratios in quasi-two-body final states have been obtained from the observation of the reactions pbarp→π+π−π0, K+K−π0,KπK0 at rest in hydrogen targets at different densities. The enhancement or suppression of specific hadronic channels connected to dynamical selection rules is observed in the production of different resonances both in protonium S and P–waves, systematically investigated for the first time. Besides the well known ρ(770)π and a2(1320)π enhancement from 3S1 and 1S0 partial waves, the dominance of one isospin source in K*(892)Kbar production, well established from S–waves, is confirmed also in P–waves (1S0, I = 0; 3S1, I = 1; 1P1, I = 0; 3P1, I = 0; 3P2, I = 1). In addition, the experimental data clearly show a strong suppression of φ(1020)π and a0(980)π final states from P–wave which has a remarkable coincidence with K*(892)Kbar pattern production.
Published: 2004

98. pbar p annihilation into four charged pions at rest and in flight

Author: P. SALVINI, V. I. TRETYAK, V. FILIPPINI, A. FONTANA, P. MONTAGNA, A. PANZARASA, A. ROTONDI, M. BRUSCHI, B. GIACOBBE, U. MARCONI, R. SPIGHI, S. VECCHI, A. BIANCONI, M. CORRADINI, A. DONZELLA, E. LODI RIZZINI, L. VENTURELLI, A. ZENONI, C. CICALÒ, A. DE FALCO, A. MASONI, G. PUDDU, S. SERCI, G. USAI, O. E. GORCHAKOV, S. N. PRAKHOV, A. M. ROZHDESTVENSKY, M. G. SAPOZHNIKOV, M. POLI, P. GIANOTTI, C. GUARALDO, A. LANARO, V. LUCHERINI, C. PETRASCU, D. PANZIERI, F. BALESTRA, M. P. BUSSA, L. BUSSO, P. CERELLO, O. DENISOV, L. FERRERO, A. GRASSO, A. MAGGIORA, F. TOSELLO, E. BOTTA, T. BRESSANI, D. CALVO, F. DE MORI, A. FELICIELLO, A. FILIPPI, S. MARCELLO, M. AGNELLO, F. IAZZI, BARGIOTTI, MARIANNE, BERTIN, ANTONIO, CAPPONI, MARCO, CARBONE, ANGELO, DE CASTRO, STEFANO, FABBRI, LAURA, FACCIOLI, PIETRO, GALLI, DOMENICO, GRIMALDI, FILIPPO, MASSA, IGNAZIO GIACOMO, PICCININI, MAURIZIO, SEMPRINI CESARI, NICOLA, VILLA, MAURO, VITALE, ANTONIO, ZOCCOLI, ANTONIO, P. SALVINI, V.I. TRETYAK, V. FILIPPINI, A. FONTANA, P. MONTAGNA, A. PANZARASA, A. ROTONDI, M. BARGIOTTI, A. BERTIN, M. BRUSCHI, M. CAPPONI, A. CARBONE, S. DE CASTRO, L. FABBRI, P. FACCIOLI, D. GALLI, B. GIACOBBE, F. GRIMALDI, U. MARCONI, I. MASSA, M. PICCININI, N. SEMPRINI CESARI, R. SPIGHI, S. VECCHI, M. VILLA, A. VITALE, A. ZOCCOLI, A. BIANCONI, M. CORRADINI, A. DONZELLA, E. LODI RIZZINI, L. VENTURELLI, A. ZENONI, C. CICALÒ, A. DE FALCO, A. MASONI, G. PUDDU, S. SERCI, G. USAI, O.E. GORCHAKOV, S.N. PRAKHOV, A.M. ROZHDESTVENSKY, M.G. SAPOZHNIKOV, M. POLI, P. GIANOTTI, C. GUARALDO, A. LANARO, V. LUCHERINI, C. PETRASCU, D. PANZIERI, F. BALESTRA, M.P. BUSSA, L. BUSSO, P. CERELLO, O. DENISOV, L. FERRERO, A. GRASSO, A. MAGGIORA, F. TOSELLO, E. BOTTA, T. BRESSANI, D. CALVO, F. DE MORI, A. FELICIELLO, A. FILIPPI, S. MARCELLO, M. AGNELLO, and F. IAZZI
Subjects: High Energy Physics::Experiment, Nuclear Experiment
Abstract: The spin-parity analysis of the data on the pbar p → 2π+ 2π− annihilation reaction at rest in liquid and in gaseous hydrogen at 3 bar pressure and in flight at p momentum of ~ 50 MeV/c, collected by the Obelix spectrometer at the LEAR complex of CERN, is presented. The relative branching ratios (a1(1260) → σπ)/(a1(1260) → ρπ) = 0.06 ± 0.05 and (π(1300) → σπ)/(π(1300) → ρπ) = 2.2 ± 0.4 are obtained. It is also shown that the inclusion of the exotic meson π1(1400), JPC= 1−+, mass and width M = 1.384 ± 0.028, Γ = 0.378 ± 0.058 GeV/c2, in its decay to ρπ, improves the fit and some implications of these results are briefly discussed. The relative S and P-wave annihilation percentages in four charged pions at two target densities are obtained.
Published: 2004

99. Study of the annihilation from S states

Author: D. Galli, G. L. Usai, Paolo Montagna, Alberto Masoni, O.E. Gorchakov, I. Massa, A M Rosca, Michelangelo Agnello, Armando Lanaro, S. Marcello, M.P. Bussa, Stefania Vecchi, C. Scoglio, F. Tosello, A. Saino, S. Tessaro, V. Filippini, S. De Castro, M. Corradini, U. Marconi, Antonietta Donzella, A.M. Rozhdestvensky, C. Cavion, Aldo Zenoni, A. Feliciello, L. Perrero, A. Vitale, D. D'Isep, B. Giacobbe, Marco Bruschi, Bruno Minetti, Alberto Rotondi, L. Vannucci, S. Serci, F. Nichitiu, A. Bertin, C. Petrascu, M. Lombardi, S. Costa, M. Poli, Elena Botta, Maurizio Piccinini, G. Vedovato, G. Pauli, M.G. Sapozhnikov, V.I. Tretyak, P.P. Temnikov, Gianfranco Zosi, Paola Gianotti, A. Maggiora, V. Lucherini, V.G. Ableev, Adriano Fontana, L. Busso, A. Ferretti, A. Collamati, Mauro Villa, L. Valacca, S.N. Prakhov, L. Venturelli, N. Semprini Cesari, R. Garfagnini, Piergiorgio Cerello, A. Grasso, Felice Iazzi, Paola Salvini, R. Spighi, A. Filippi, L. Santi, G. Maron, Corrado Cicalo, R. Donà, F. Vigotti, M. Capponi, Tullio Bressani, U. Gastaldi, F. Balestra, C. Guaraldo, G. Bendiscioli, O.Yu. Denisov, E. Lodi Rizzini, Antonio Zoccoli, G. Puddu, E. Rossetto, D. Panzieri, and K. Calvo
Subjects: Momentum, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Annihilation, Meson, State (functional analysis)
Abstract: The results of the spin-parity analysis of annihilations at very low momentum (≈ 50 MeV/c) are reported. To describe the data the production of the ϱ, f2, a2 and a1 mesons and the presence of the ππ interaction in S-wave (the σ term) in the final state are necessary. The best fit solution requires also the presence of a ϱ′ state of mass and width M = 1.282 ± 0.037, Γ = 0.236 ± 0.036 GeV/c2 and of a heavy pion π(1300) of mass and width M = 1.275 ± 0.015, Γ = 0.218 ± 0.100 GeV/c2. The measured fraction of the annihilation cross section into 2π+2π− is (7.61 ± 0.35) · 10−2.
Published: 1997

100. Study of annihilation in two mesons in the momentum range between 50 to 400 MeV/c with OBELIX

Author: P.P. Temnikov, Antonietta Donzella, Paolo Montagna, Stefania Vecchi, S. Costa, Elena Botta, L. Fava, Adriano Fontana, A.M. Rozhdestvensky, M.G. Sapozhnikov, I. Massa, R. Garfagnini, M. Corradini, S. Marcello, Marco Bruschi, Alberto Masoni, Paola Salvini, S.N. Prakhov, G. Pauli, L. Ferrero, Massimo Piccinini, F. Vigotti, D. Calvo, A. Vezzani, Bruno Minetti, Antonio Ferretti, L. Valacca, V.G. Ableev, S. Decastro, Alberto Rotondi, L. Venturelli, S. Serci, C. Petrascu, F. Nichitiu, L. Busso, O.E. Gorchakov, D. Parena, M. Poli, G. Vedovato, Tullio Bressani, F. Tosello, A. Saino, A M Rosca, Maria Pia Bussa, U. Gastaldi, S. Tessaro, V.I. Tretyak, G. L. Usai, G. Maron, O. Y. Denisov, A. Maggiora, Paola Gianotti, M. Lombardi, A. Collamati, Mauro Villa, V. Lucherini, M. Capponi, L. Vannucci, D. Galli, V. Filippini, G. Puddu, V. Vagnoni, L. Santi, Felice Iazzi, Armando Lanaro, C. Cavion, Roberto Spighi, Corrado Cicalo, Aldo Zenoni, Nicola Semprini-Cesari, D. Panzieri, C. Scoglio, A. Vitale, A. Grasso, Umberto Marini Bettolo Marconi, E. Rossetto, E. L. Rizzini, Alessandro Feliciello, Benedetto Giacobbe, G. Bendiscioli, A. Filippi, R. Donà, C. Guaraldo, A.E. Kudryavtsev, P. Cerello, A. Bertin, Michelangelo Agnello, F. Balestra, L. Filippi, and Antonio Zoccoli
Subjects: Momentum, Physics, Nuclear physics, Nuclear and High Energy Physics, Range (particle radiation), Annihilation, Deuterium, Meson, Atomic physics, Antineutron, Bar (unit)
Abstract: We measured the in flight annihilation frequencies and cross sections of reactions n p → π + π 0 ,π + η and K+KS in the antineutron momentum range between 50 and 400 MeV/c. The annihilation frequencies of these channels from the different allowed initial states were calculated and some information about the n p annihilation dynamics were obtained. The first determination of the D-wave contribution in this momentum range was also obtained.
Published: 1997

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