Search

Your search keyword '"P. Courtat"' showing total 68 results
Start Over Author "P. Courtat"
68 results on '"P. Courtat"'

1. Compression of Recurrent Neural Networks using Matrix Factorization

Author

Maison, Lucas, Bourboux, Hélion du Mas des, and Courtat, Thomas

Subjects
Computer Science - Machine Learning, Computer Science - Artificial Intelligence, Statistics - Machine Learning
Abstract

Compressing neural networks is a key step when deploying models for real-time or embedded applications. Factorizing the model's matrices using low-rank approximations is a promising method for achieving compression. While it is possible to set the rank before training, this approach is neither flexible nor optimal. In this work, we propose a post-training rank-selection method called Rank-Tuning that selects a different rank for each matrix. Used in combination with training adaptations, our method achieves high compression rates with no or little performance degradation. Our numerical experiments on signal processing tasks show that we can compress recurrent neural networks up to 14x with at most 1.4% relative performance reduction.

Published
2023

2. Greedy Gradient-free Adaptive Variational Quantum Algorithms on a Noisy Intermediate Scale Quantum Computer

Author

Feniou, César, Claudon, Baptiste, Hassan, Muhammad, Courtat, Axel, Adjoua, Olivier, Maday, Yvon, and Piquemal, Jean-Philip

Subjects
Quantum Physics, Physics - Chemical Physics
Abstract

Hybrid quantum-classical adaptive Variational Quantum Eigensolvers (VQE) already hold the potential to outperform classical computing for simulating quantum many-body systems. However, their practical implementation on current quantum processing units (QPUs) is very challenging due to the noisy evaluation of a polynomially scaling number of observables, undertaken for operator selection and optimisation of a high-dimensional cost function. To overcome this, we propose new techniques to execute adaptive algorithms on a 25-qubit error-mitigated QPU coupled to a GPU-accelerated HPC simulator. Targeting physics applications, we compute the ground state of a 25-body Ising model using the newly introduced Greedy Gradient-free Adaptive VQE (CGA-VQE) requiring only five circuit measurements per iteration, regardless of the number of qubits and size of the operator pool. Towards chemistry, we combine the GGA-VQE and Overlap-ADAPT-VQE algorithms to approximate a molecular system ground state. We show that the QPU successfully executes the algorithms and yields the correct choice of parametrised unitary operators. While the QPU evaluation of the resulting ansatz wave-function is polluted by hardware noise, a single final evaluation of the sought-after observables on a classical GPU-accelerated/noiseless simulator allows the recovery of the correct approximation of the ground state, thus highlighting the need for hybrid quantum-classical observable measurement.

Published
2023

3. A light neural network for modulation detection under impairments

Author

Courtat, Thomas and Bourboux, Hélion du Mas des

Subjects
Computer Science - Machine Learning, Electrical Engineering and Systems Science - Signal Processing, Statistics - Machine Learning
Abstract

We present a neural network architecture able to efficiently detect modulation scheme in a portion of I/Q signals. This network is lighter by up to two orders of magnitude than other state-of-the-art architectures working on the same or similar tasks. Moreover, the number of parameters does not depend on the signal duration, which allows processing stream of data, and results in a signal-length invariant network. In addition, we have generated a dataset based on the simulation of impairments that the propagation channel and the demodulator can bring to recorded I/Q signals: random phase shifts, delays, roll-off, sampling rates, and frequency offsets. We benefit from this dataset to train our neural network to be invariant to impairments and quantify its accuracy at disentangling between modulations under realistic real-life conditions. Data and code to reproduce the results are made publicly available., Comment: 7 pages, 4 figures, presented at the 2021 International Symposium on Networks, Computers and Communications (ISNCC)

Published
2020
Full Text
View/download PDF

4. Stochastic simulation of urban environments. Application to Path-loss in wireless systems

Author

Courtat, Thomas, Decreusefond, Laurent, and Martins, Phillipe

Subjects
Mathematics - Probability
Abstract

We are interested in the assessment of electromagnetic Path-Loss in complex environments. The Path-loss is the attenuation function $P$ of the electromagnetic power at a distance $d$ of an antenna. In free-space, $P(d) \propto 1/d^2$, in complex environments like cities, wave trajectory is altered by successive reflections and absorptions, the path-loss is not theoretically known and engineering rules postulate that $P(d) \simeq 1/d^{\gamma}, \, \gamma>2$. We place in a stochastic geometry context to answer the problem statistically. We present random models of 3D-city. These models reproduce main real cities' features, can be calibrated with simple mean formulae and can be fast simulated. For collections of random cities with the same mean morphology, we estimate by Monte-Carlo ray tracing techniques their attenuation maps. By averaging these maps, we show that the power expectancy actually follows a function $\sim 1/d^{\gamma}$ with $\gamma$ depending on the environment morphology.

Published
2016

5. Hypergraphs and City Street Networks

Author

Courtat, Thomas, Gloaguen, Catherine, and Douady, Stéphane

Subjects
Physics - Physics and Society, Computer Science - Social and Information Networks
Abstract

The map of a city's streets constitutes a particular case of spatial complex network. However a city is not limited to its topology: it is above all a geometrical object whose particularity is to organize into short and long axes called streets. In this article we present and discuss two algorithms aiming at recovering the notion of street from a graph representation of a city. Then we show that the length of the so-called streets scales logarithmically. This phenomenon leads to assume that a city is shaped into a logic of extension and division of space.

Published
2011

6. Mathematics and Morphogenesis of the City: A Geometrical Approach

Author

Courtat, Thomas, Gloaguen, Catherine, and Douady, Stephane

Subjects
Nonlinear Sciences - Adaptation and Self-Organizing Systems, Mathematical Physics, Physics - Physics and Society
Abstract

Cities are living organisms. They are out of equilibrium, open systems that never stop developing and sometimes die. The local geography can be compared to a shell constraining its development. In brief, a city's current layout is a step in a running morphogenesis process. Thus cities display a huge diversity of shapes and none of traditional models from random graphs, complex networks theory or stochastic geometry takes into account geometrical, functional and dynamical aspects of a city in the same framework. We present here a global mathematical model dedicated to cities that permits describing, manipulating and explaining cities' overall shape and layout of their street systems. This street-based framework conciliates the topological and geometrical sides of the problem. From the static analysis of several French towns (topology of first and second order, anisotropy, streets scaling) we make the hypothesis that the development of a city follows a logic of division / extension of space. We propose a dynamical model that mimics this logic and which from simple general rules and a few parameters succeeds in generating a large diversity of cities and in reproducing the general features the static analysis has pointed out., Comment: 13 pages, 13 figures

Published
2010
Full Text
View/download PDF

8. Possible Indication of Narrow Baryonic Resonances Produced in the 1720-1790 MeV Mass Region

Author

Tatischeff, B., Yonnet, J., Boivin, M., Comets, M. P., Courtat, P., Gacougnolle, R., Bornec, Y. Le, Loireleux, E., MacCormick, M., Reide, F., and Willis, N.

Subjects
Nuclear Experiment
Abstract

Signals of two narrow structures at M=1747 MeV and 1772 MeV were observed in the invariant masses M_{pX} and M_{\pi^{+}X} of the pp->ppX and pp->p\pi^{+}X reactions respectively. Many tests were made to see if these structures could have been produced by experimental artefacts. Their small widths and the stability of the extracted masses lead us to conclude that these structures are genuine and may correspond to new exotic baryons. Several attempts to identify them, including the possible "missing baryons" approach, are discussed., Comment: 17 pages including 8 figures and 3 tables. ReVtex

Published
2004
Full Text
View/download PDF

9. Experimental evidence for narrow baryons in the mass range 1.0$\le$ M $\le$1.46 GeV

Author

Tatischeff, B., Boivin, M., Comets, M. P., Courtat, P., Gacougnolle, R., Bornec, Y. Le, Loireleux, E., Reide, F., and Willis, N.

Subjects
Nuclear Experiment
Abstract

The reaction p p $\to$ p ${\pi^+}X$ was studied at different incident energies around T$_{p}$=2 GeV. Narrow baryonic structures were observed in the missing mass M$_{X}$ and in the invariant mass M$_{p\pi^{+}}$. The masses of these structures are: 1004, 1044, 1094, 1136, 1173, 1249, 1277, and 1384 MeV (and possibly 1339 MeV). Some of them were also observed at the same masses in the missing mass spectra of the d p $\to$ p p X reaction although with a weaker signature. Many checks were performed to make sure that these structures were not produced by experimental artifacts. Several narrow small amplitude peaks, were also extracted using already published photo-nucleon cross sections. The small widths of all these results, and the stability of the observed structures, regardless of the experiment, were used to conclude that they are genuine baryons which and not merely the consequence of dynamical rescatterings. These baryons cannot be associated with classical $q^{3}$ quark configurations. We associate them with two colored cluster quark configurations., Comment: 42 figures, 10 tables, revtex

Published
2002

10. Near-threshold eta production in the p d -> p d eta reaction

Author

Hibou, F., Wilkin, C., Bergdolt, A. M., Bergdolt, G., Bing, O., Boivin, M., Bouchakour, A., Brochard, F., Combes-Comets, M. P., Courtat, P., Gacougnolle, R., Bornec, Y. Le, Moalem, A., Plouin, F., Reide, F., Tatischeff, B., and Willis, N.

Subjects
Nuclear Experiment
Abstract

The total cross section of the p d -> p d eta reaction has been measured at two energies near threshold by detecting the final proton and deuteron in a magneti spectrometer. The values are somewhat larger than expected on the basis of two simple theoretical estimates., Comment: 13 pages, LaTeX, 4 eps figures

Published
2000
Full Text
View/download PDF

11. Near-Threshold Production of omega Mesons in the pp -> pp omega Reaction

Author

Hibou, F., Bing, O., Boivin, M., Courtat, P., Gacougnolle, R., Bornec, Y. Le, Martin, J. M., Plouin, F., Tatischeff, B., Wilkin, C., Willis, N., and Wurzinger, R.

Subjects
Nuclear Experiment
Abstract

The total cross section for omega production in the pp -> pp omega reaction has been measured at five c.m. excess energies from 3.8 to 30 MeV. The energy dependence is easily understood in terms of a strong proton-proton final state interaction combined with a smearing over the width of the state. The ratio of near-threshold phi and omega production is consistent with the predictions of a one-pion-exchange model and the degree of violation of the OZI rule is similar to that found in the pi-p -> n omega/phi reactions., Comment: Report in LaTeX2e. 12 pages with 2 eps figures

Published
1999
Full Text
View/download PDF

12. Study of the ABC Enhancement in the d d -> alpha X reaction

Author

Wurzinger, R., Bing, O., Boivin, M., Courtat, P., Faldt, G., Gacougnolle, R., Gardestig, A., Hibou, F., Bornec, Y. Le, Martin, J. M., Plouin, F., Tatischeff, B., Wilkin, C., Willis, N., Yonnet, J., and Zghiche, A.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The polarized d d -> alpha X reaction at beam energies close to the eta threshold shows very strong structure in the missing mass corresponding to the ABC enhancement. The deuteron tensor analysing power A_yy, and the slope of the vector analysing power A_y with respect to angle, have been measured for this reaction around the forward direction. Both signals are small, and their variations with the alpha-particle momentum are in broad agreement with a theoretical model in which each pair of nucleons in the projectile and target deuterons undergoes pion production through the NN -> d pi reaction., Comment: LaTeX2e, 10 pages, 3 eps figures, submitted to Physics Letters B

Published
1998
Full Text
View/download PDF

13. Comparison of eta and eta' production in the pp -> pp eta(eta') reactions near threshold

Author

Hibou, F., Bing, O., Boivin, M., Courtat, P., Faldt, G., Gacougnolle, R., Bornec, Y. Le, Martin, J. M., Moalem, A., Plouin, F., Taleb, A., Tatischeff, B., Wilkin, C., Willis, N., and Wurzinger, R.

Subjects
Nuclear Experiment
Abstract

The total cross section of the pp -> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production, in good agreement with the predictions of a one-pion-exchange model., Comment: 10 pages, Latex with 3 eps figures

Published
1998
Full Text
View/download PDF

14. Subthreshold K+ production in deuteron and alpha induced nuclear reactions

Author

Debowski, M., Senger, P., Boivin, M., LeBornec, Y., Courtat, P., Gacougnolle, R., Grosse, E., Kabana, S., Kirchner, T., Koczon, P., Mang, M., Schwab, E., Tatischeff, B., Wagner, A., Walus, W., Willis, N., Wolf, G., Wurzinger, R., and Yonnet, J.

Subjects
Nuclear Experiment
Abstract

Double differential cross sections have been measured for pi+ and K+ emitted around midraidity in d+A and He+A collisions at a beam kinetic energy of 1.15 GeV/nucleon. The total pi+ yield increases by a factor of about 2 when using an alpha projectile instead of a deuteron whereas the K+ yield increases by a factor of about 4. According to transport calculations, the K+ enhancement depends both on the number of hadron-hadron collisions and on the energy available in those collisions: their center-of-mass energy increases with increasing number of projectile nucleons.

Published
1997

15. Eta-Helium Quasi-Bound States

Author

Willis, N., Bornec, Y. Le, Zghiche, A., Wilkin, C., Wurzinger, R., Bing, O., Boivin, M., Courtat, P., Gacougnolle, R., Hibou, F., Martin, J. M., Plouin, F., Tatischeff, B., and Yonnet, J.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, Nuclear Theory
Abstract

The cross section and tensor analysing power t_20 of the d\vec{d}->eta 4He reaction have been measured at six c.m. momenta, 10 < p(eta) < 90 MeV/c. The threshold value of t_20 is consistent with 1/\sqrt{2}, which follows from parity conservation and Bose symmetry. The much slower momentum variation observed for the reaction amplitude, as compared to that for the analogous pd->eta 3He case, suggests strongly the existence of a quasi-bound state in the eta-4He system and optical model fits indicate that this probably also the case for eta-3He., Comment: LaTeX, uses elsart.sty, 10 pages, 3 Postscript figures, Submitted to Physics Letters B

Published
1997
Full Text
View/download PDF

18. Subthreshold K+ production in proton-nucleus collisions

Author

Dębowski, M., Barth, R., Boivin, M., Le Bornec, Y., Cieślak, M., Comets, M. P., Courtat, P., Gacougnolle, R., Grosse, E., Kirchner, T., Martin, J. M., Miśkowiec, D., Müntz, C., Schwab, E., Senger, P., Sturm, C., Tatischeff, B., Wagner, A., Waluś, W., Willis, N., Wurzinger, R., Yonnet, J., and Zghiche, A.

Published
1996
Full Text
View/download PDF

19. Secuelas otológicas de los traumatismos craneocervicales

Author

C. Peytral, P. Courtat, E. Chevalier, and F. Parvy

Subjects
General Medicine
Abstract

Las secuelas audiovestibulares son muy frecuentes en los traumatismos craneocervicales, observandose en mas del 75% de los accidentes de trafico o durante los accidentes laborales. El estudio fisiopatologico distingue los traumatismos craneales con o sin lesion osea y describe las lesiones timpanoosiculares, las alteraciones laberinticas y las lesiones faciales y meningeas. Las lesiones otologicas que se producen durante los traumatismos cervicales se consideran por separado. Para evaluar los diferentes elementos de los trastornos postraumaticos de la audicion y del equilibrio, se estudian la clinica, las exploraciones instrumentales especificas y las pruebas de imagen. Los criterios fundamentales de imputabilidad de una lesion auditiva o vestibular se exponen antes de la evaluacion de la lesion. Por ultimo, se describen a modo de ejemplo diversos baremos aplicables en otorrinolaringologia (ORL) utilizados en Francia en diferentes ambitos (derecho comun, funcion publica e incapacidades).

Published
2006

20. Séquelles otologiques des traumatismes craniocervicaux

Author

C. Peytral, E. Chevalier, F. Parvy, and P. Courtat

Subjects
Gynecology, medicine.medical_specialty, Otorhinolaryngology, business.industry, medicine, Temporal bone fracture, LPN and LVN, business, Cranial trauma
Abstract

Les sequelles audiovestibulaires sont tres frequentes au cours des traumatismes craniocervicaux rencontres dans plus de 75 % des accidents de la voie publique ou lors de traumatismes professionnels. Cette etude physiopathologique distingue les traumatismes crâniens avec et sans lesion osseuse, et decrit les lesions tympano-ossiculaires, les atteintes labyrinthiques, les atteintes faciales et meningees. Les lesions otologiques observees lors des traumatismes cervicaux sont isolees. Les differents elements d'evaluation d'un trouble auditif et d'un trouble de l'equilibre post-traumatiques sont etudies par la clinique, les explorations specifiques instrumentales et l'imagerie. Les criteres fondamentaux d'imputabilite d'une lesion auditive ou vestibulaire sont exposes avant l'evaluation du dommage. Les baremes applicables a l'oto-rhino-laryngologie (ORL) sont successivement rappeles : en droit commun, en accident de travail, dans la fonction publique et pour les handicapes.

Published
2006

21. Experimental evidence for narrow baryons in the mass range 1.0≤M≤1.46 GeV

Author

N. Willis, Y. Le Bornec, E. Loireleux, M. P. Comets, P. Courtat, M. Boivin, F. Reide, M. MacCormick, B. Tatischeff, R. Gacougnolle, and J. Yonnet

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Nuclear Theory, Hadron, Nuclear physics, Baryon, Effective mass (solid-state physics), Mass spectrum, Invariant mass, Nuclear Experiment, Nucleon
Abstract

The reaction pp → pπ+ X was studied at different incident energies around T p = 2 GeV. Narrow baryonic structures were observed in the missing mass M X and in the invariant mass M pπ{+}. The masses of these structures are 1004, 1044, 1094, 1136, 1173, 1249, 1277, and 1384 MeV (and possibly 1339 MeV). Some of them were also observed at the same masses in the missing-mass spectra of the dp → ppX reaction although with a weaker signature. Many checks were performed to make sure that these structures were not produced by experimental artifacts. Several narrow small-amplitude peaks, were also extracted using already published photonucleon cross-sections. The small widths of all these results, and the stability of the observed structures, regardless of the experiment, were used to conclude that they are genuine baryons and not merely the consequence of dynamical rescatterings. These baryons cannot be associated with classical q3 quark configurations. We associate them with two colored-quark cluster configurations.

Published
2003

22. Near-threshold η production in the pd→pdη reaction

Author

F. Brochard, R. Gacougnolle, F. Reide, Y. Le Bornec, A. Moalem, P. Courtat, M. Boivin, B. Tatischeff, O. Bing, A. Bouchakour, N. Willis, A.M. Bergdolt, G. Bergdolt, F. Plouin, M.P. Combes-Comets, F. Hibou, and Colin Wilkin

Subjects
Physics, Nuclear and High Energy Physics, Cross section (physics), SIMPLE (dark matter experiment), Meson, Spectrometer, Proton, Deuterium, Nuclear Theory, Hadron, Nuclear fusion, Atomic physics, Nuclear Experiment
Abstract

The total cross section of the pd→pdη reaction has been measured at two energies near threshold by detecting the final proton and deuteron in a magnetic spectrometer. The values are somewhat larger than expected on the basis of two simple theoretical estimates.

Published
2000

23. Near-Threshold Production ofωMesons in thepp→ppωReaction

Author

J. M. Martin, O. Bing, R. Gacougnolle, F. Hibou, F. Plouin, P. Courtat, N. Willis, Y. Le Bornec, Colin Wilkin, R. Wurzinger, B. Tatischeff, and M. Boivin

Subjects
Physics, Particle physics, Degree (graph theory), Meson, 010308 nuclear & particles physics, General Physics and Astronomy, State (functional analysis), 01 natural sciences, Omega, Near threshold, 0103 physical sciences, Production (computer science), Nuclear Experiment, 010306 general physics, Energy (signal processing)
Abstract

The total cross section for $\ensuremath{\omega}$ production in the $\mathrm{pp}\ensuremath{\rightarrow}\mathrm{pp}\ensuremath{\omega}$ reaction has been measured at 5 c.m. excess energies from 3.8 to 30 MeV. The energy dependence is easily understood in terms of a strong proton-proton final state interaction combined with a smearing over the width of the state. The ratio of near-threshold $\ensuremath{\varphi}$ and $\ensuremath{\omega}$ production is, to within relatively large uncertainties, consistent with the predictions of a simple one-pion-exchange model. The degree of violation of the Okubo-Zweig-Iizuka rule is similar to that found in the ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}n\ensuremath{\omega}/\ensuremath{\varphi}$ reactions.

Published
1999

25. Study of the ABC enhancement in the reaction

Author

A. Zghiche, R. Gacougnolle, N. Willis, J. Yonnet, Anders Gardestig, F. Hibou, B. Tatischeff, O. Bing, Colin Wilkin, F. Plouin, P. Courtat, Göran Fäldt, Jérôme Martin, M. Boivin, Y. Le Bornec, and R. Wurzinger

Subjects
Momentum, Physics, Nuclear and High Energy Physics, Pion, Deuterium, Projectile, Nuclear Theory, Alpha (ethology), Tensor, Atomic physics, Nuclear Experiment, Nucleon, Beam (structure)
Abstract

The polarized d d -> alpha X reaction at beam energies close to the eta threshold shows very strong structure in the missing mass corresponding to the ABC enhancement. The deuteron tensor analysing power A_yy, and the slope of the vector analysing power A_y with respect to angle, have been measured for this reaction around the forward direction. Both signals are small, and their variations with the alpha-particle momentum are in broad agreement with a theoretical model in which each pair of nucleons in the projectile and target deuterons undergoes pion production through the NN -> d pi reaction.

Published
1999

26. Comparison of η and η′ production in the reactions near threshold

Author

A. Moalem, P. Courtat, M. Boivin, Jérôme Martin, R. Wurzinger, A. Taleb, Colin Wilkin, F. Hibou, Göran Fäldt, B. Tatischeff, R. Gacougnolle, F. Plouin, Y. Le Bornec, N. Willis, and O. Bing

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Cross section (physics), Near threshold, Spectrometer, Nuclear Experiment
Abstract

The total cross section of the pp -> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production, in good agreement with the predictions of a one-pion-exchange model.

Published
1998

27. Analyzing powers of one and two Δ production in inelastic pp reactions at energies between 1.5 and 2.1 GeV

Author

F. Reide, R. Gacougnolle, B. Tatischeff, M. P. Comets, J. Yonnet, M.P. Rekalo, M. Boivin, Y. Le Bornec, N. Willis, E. Loireleux, and P. Courtat

Subjects
Baryon, Nuclear physics, Physics, Nuclear reaction, Nuclear and High Energy Physics, Pion, Meson, Hadron, Atomic physics, Inelastic scattering, Nucleon, Delta baryon
Abstract

The reaction pp → pπ+X was studied at three energies (Tp = 1520, 1805 and 2100 MeV). The analyzing powers of pp → ΔΔ, pp → Δn and pp → pπ+X reactions (0.94 < MX < 1.5 GeV) were extracted between 0° and 17° in the lab, which corresponds to an angular range between 0° and 100° (c.m.). A theoretical analysis was performed based on s-channel contributions in 2+ and 1− intermediate states. The resulting formulas allow us to obtain good fits with experimental data.

Published
1998

28. Evidence for Narrow Baryon Resonances in InelasticppScattering

Author

N. Willis, R. Gacougnolle, M. Boivin, F. Reide, M. P. Comets, P. Courtat, J. Yonnet, B. Tatischeff, Y. Le Bornec, and E. Loireleux

Subjects
Baryon, Physics, Mass formula, Color model, Particle physics, Degree (graph theory), Hadron, Quark model, General Physics and Astronomy, Elementary particle, Inelastic scattering, Atomic physics
Abstract

The reaction pp{r_arrow}p{pi}{sup +}N has been studied at three energies (T{sub p}=1520 , 1805, and 2100MeV) and six angles from 0{degree} up to 17{degree} (laboratory). Several narrow states have been observed in missing mass spectra at 1004, 1044, and 1094MeV. Their widths are typically 1 order of magnitude smaller than the widths of N{sup {asterisk}} or {Delta} . Possible biases are discussed. These masses are in good agreement with those calculated within a simple phenomenological mass formula based on color magnetic interaction between two colored quark clusters. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

29. η-helium quasi-bound states

Author

P. Courtat, R. Gacougnolle, Jérôme Martin, O. Bing, N. Willis, F. Plouin, Colin Wilkin, J. Yonnet, B. Tatischeff, F. Hibou, Y. Le Bornec, A. Zghiche, R. Wurzinger, M. Boivin, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, chemistry.chemical_element, State (functional analysis), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), Cross section (physics), chemistry, Quantum mechanics, 0103 physical sciences, Bound state, High Energy Physics::Experiment, Tensor, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Helium
Abstract

The cross section and tensor analysing power t_20 of the d\vec{d}->eta 4He reaction have been measured at six c.m. momenta, 10 < p(eta) < 90 MeV/c. The threshold value of t_20 is consistent with 1/\sqrt{2}, which follows from parity conservation and Bose symmetry. The much slower momentum variation observed for the reaction amplitude, as compared to that for the analogous pd->eta 3He case, suggests strongly the existence of a quasi-bound state in the eta-4He system and optical model fits indicate that this probably also the case for eta-3He., LaTeX, uses elsart.sty, 10 pages, 3 Postscript figures, Submitted to Physics Letters B

Published
1997

30. Subthreshold K+ production in proton-nucleus collisions

Author

De̹bowski, M., Barth, R., Boivin, M., Le Bornec, Y., Cieślak, M., Comets, M. P., Courtat, P., Gacougnolle, R., Grosse, E., Kirchner, T., Martin, J. M., Miśkowiec, D., Müntz, C., Schwab, E., Senger, P., Sturm, C., Tatischeff, B., Wagner, A., Waluś, W., Willis, N., Wurzinger, R., Yonnet, J., and Zghiche, A.

Published
1987
Full Text
View/download PDF

31. Measurement of tensor polarization of deuterons from3He→d+pbreakup at momenta from 4.60 to 5.66 GeV/c

Author

L. V. Malinina, J. Ball, J.-L. Sans, R. Gacougnolle, R.A. Kunne, J. L. Boyard, L. Bimbot, E. Tomasi-Gustafsson, E. A. Strokovsky, V. A. Punjabi, S. Nedev, P. Courtat, L. B. Golovanov, J. Yonnet, R. Skowron, I.M. Sitnik, C. F. Perdrisat, N.M. Piskunov, Y. Bisson, M. K. Jones, Yu. T. Borzunov, M. Boivin, and T. Hennino

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Elementary particle, Few-body systems, 01 natural sciences, 7. Clean energy, Nuclear physics, Baryon, Helium-3, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon, Isotopes of helium
Abstract

The tensor polarization ${\ensuremath{\rho}}_{20}$ of deuterons emitted in the ${}^{1}\mathrm{H}{(}^{3}\mathrm{He},\stackrel{\ensuremath{\leftrightarrow}}{d})X$ reaction at ${0}^{\ensuremath{\circ}}$ in the laboratory system was measured at the Saturne National Laboratory in Saclay using the SPES-4 spectrometer with the HYPOM polarimeter located downstream from its focal plane. The momentum of the detected deuterons was kept fixed at 3.77 GeV$/c$, while the momentum of the ${}^{3}\mathrm{He}$ beam was varied from 4.60 to 5.66 GeV$/c$, thus providing a range of internal momenta $k$ of the deuteron in ${}^{3}\mathrm{He}$ from 0 up to 0.4 GeV$/c$. The data obtained are compared with theoretical predictions.

Published
2011

32. Total cross section of thepp→ppηreaction near threshold

Author

M.P. Combes-Comets, P. Courtat, F. Reide, R. Gacougnolle, Y. Le Bornec, E. Loireleux, A. Taleb, G. Bergdolt, F. Brochard, F. Hibou, F. Plouin, N. Willis, O. Bing, M. Boivin, A. Moalem, B. M. K. Nefkens, A.M. Bergdolt, B. Tatischeff, and A. Bouchakour

Subjects
Physics, Nuclear reaction, Nuclear physics, Meson, Hadron, Dalitz plot, Scattering length, Elementary particle, Threshold energy, Boson
Abstract

The [ital pp][r arrow][ital pp][eta] reaction is studied at energies near the [eta] production threshold. The total cross sections at nominal machine energies of 1260, 1265, and 1300 MeV are 90[plus minus]15, 790[plus minus]120, and 3460[plus minus]690 nb, respectively. None of the existing perturbative model calculations reproduces the energy dependence, which deviates strongly from phase space. This suggests that the cross section is enhanced in the near vicinity of the production threshold by a large [eta]-[ital pp] scattering length.

Published
1993

33. Search for dibaryonic states in the p-p analyzing power excitation function

Author

J. Saudinos, J. Yonnet, J. L. Boyard, R. Gacougnolle, P. Courtat, J. Arvieux, J.M. Durand, M.P. Combes-Comets, M. Garçon, M. Boivin, J.C. Duchazeaubeneix, Y. Le Bornec, N. Willis, B. Tatischeff, R. Beurtey, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Robert, Suzanne

Subjects
Excitation function, Physics, Nuclear and High Energy Physics, Nuclear magnetic resonance, Amplitude, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], 010308 nuclear & particles physics, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Atomic physics, 010306 general physics, 01 natural sciences, Power (physics)
Abstract

The analyzing power excitation function has been measured with high accuracy between 510 and 725 MeV. The 182 measured points show no structure of an amplitude 4×10 −3 or more.

Published
1992

34. Search for multibaryonic resonances in the reaction

Author

R. Frascaria, M.P. Combes-Comets, O. Bing, Y. Le Bornec, M. Boivin, N. Willis, F. Hibou, G. Bergdolt, Elie Aslanides, D. Benabdelouahed, P. Fassnacht, F. Reide, A.M. Bergdolt, B. Tatischeff, C. Kerboul, and P. Courtat

Subjects
Baryon, Physics, Nuclear reaction, Nuclear and High Energy Physics, Spectrometer, Resonance, Incident energy, Atomic physics
Abstract

The reaction p + d → π − + X has been studied at Saturne at 1.45, 2.10 and 2.70 GeV, using the spectrometer SPES III. The analysing power and the differential cross sections show no evidence for narrow structures which could be interpreted as a resonance in the three baryon system. At the lowest incident energy, the shapes of the experimental cross sections are well reproduced by phase-space distributions.

Published
1991

35. ALICE: Physics Performance Report, Volume II

Author

Alessandro, B. Antinori, F. Belikov, J. A. Blume, C. and Dainese, A. Foka, P. Giubellino, P. Hippolyte, B. Kuhn, C. Martinez, G. Monteno, M. Morsch, A. Nayak, T. K. and Nystrand, J. Noriega, M. Lopez Paic, G. Pluta, J. and Ramello, L. Revol, J-P Safarik, K. Schukraft, J. Schutz, Y. Scomparin, E. Snellings, R. Baillie, O. Villalobos and Vercellin, E. Cortese, P. Dellacasa, G. Ramello, L. and Sitta, M. Ahmad, N. Ahmad, S. Ahmad, T. Bari, W. and Irfan, M. Zafar, M. Botje, M. Kuijer, P. G. Snellings, R. Belogianni, A. Christakoglou, P. Ganoti, P. Petridis, A. Roukoutakis, F. Spyropoulou-Stassinaki, M. Vassiliou, M. and Bruno, G. E. Cali, I. A. Caselle, M. De Cataldo, G. and Di Bari, D. Elia, D. Fini, R. A. Ghidini, B. Lenti, V. and Manzari, V. Mastroserio, A. Minafra, F. Nappi, E. and Navach, F. Pastore, C. Paticchio, V. Perrino, D. Posa, F. Santoro, R. Sgura, I Volpe, G. Corsi, F. De Venuto, D. Fratino, U. Marzocca, C. Tauro, A. Li, X. and Liu, Z. Lu, S. Lu, Z. Meng, Q. Sa, B. Yuan, J. and Zhou, J. Zhou, S. Alme, J. Bablok, S. Klovning, A. and Nystrand, J. Pommereesche, B. Richter, M. Rohrich, D. and Ullaland, K. Yang, H. Helstrup, H. Hetland, K. F. and Kileng, B. Roed, K. Choudhury, R. K. Dash, S. Mahapatra, D. P. Mishra, D. Phatak, S. C. Sahoo, R. Daniel, L. and Evans, D. Jones, G. T. Jovanovic, P. Jusko, A. Kinson, J. B. Platt, R. Lietava, R. Takaki, J. D. Tapia Baillie, O. Villalobos Alici, A. Antinori, S. Antoniolo, P. and Arcelli, S. Bari, G. Basile, M. Romeo, G. Cara and Cifarelli, L. Cindolo, F. Falchieri, D. Gabrielli, A. and Gandolfi, E. Hatzifotiadou, D. Laurenti, G. Luvisetto, M. I. and Nania, R. Noferini, F. Palmonari, F. Pesci, A. and Sartorelli, G. Sciolo, G. Vacca, G. P. Valenti, G. and Venturi, G. Williams, M. C. S. Zampolli, C. Zichichi, A. and Cerny, V. Janik, R. Lucan, L. Pikna, M. Pisut, J. and Pisutova, N. Sitar, B. Strmen, P. Szarka Zagiba, M. and Aiftimieri, C. Catanescu, V. Legrand, C. I. Petrovici, M. and Pop, A. Schiaua, C. Simion, V. Barnafoldi, G. and Boldizsar, L. Denes, E. Fodor, Z. Futo, E. Kiss, T. and Levai, P. Palla, G. Zimanyi, J. Atanassov, I. Basciu, S. and Cicalo, C. De Falco, A. Floris, M. Masoni, A. Mura, D. Puddu, G. Serci, S. Siddi, S. Usai, G. Badala, A. and Barbera, R. Lo Re, G. Palmeri, A. Pappalardo, G. S. and Pulvirenti, A. Riggi, F. Anelli, G. Augustin, I. and Augustinus, A. Baechler, J. Belikov, J. A. Betev, L. and Boccardi, A. Brun, R. Burns, M. Buncic, P. Campagnolo, R. Campbell, M. Carena, F. Carena, W. Carminati, F. and Chapeland, S. Cheshkov, C. Chochula, P. Christiansen, P. and Colla, A. Belbute, B. F. Correia Davenport, M. de Groot, J. and Di Mauro, A. Divia, R. Engster, C. Evrard, S. and Fabjan, C. W. Feng, L. Flierl, D. Formenti, F. Fuchs, U. and Garcia Lopez, A. Gheata, A. Gheata, M. and Gonzalez-Gutierrez, C. Grosso, R. Gruwe, M. Gustafsson, H. A. Hoedelmoser, H. Hristov, P. Ivanov, M. Jirden, L. and Jorgensen, C. Junique, A. Kapusta, S. Kickinger, W. and Klempt, W. Kluge, A. Leistam, L. Lo, J. P. Noriega, M. Lopez Lourenco, C. Makhylyueve, I. Marin, J. C. and Martinengo, P. Meunier-Picard, D. Meoni, M. Morel, M. and Morsch, A. Mota, B. Muller, H. Musa, L. Nayak, T. K. and Nilsson, P. Nouais, D. Osmic, F. Perini, D. Pestotnik, R. Peters, A. Morais, V. Pinto Popescu, S. Rademakers, F. Revol, J. P. Riedler, P. Riegler, W. Safarik, K. and Schossmaier, K. Schukraft, J. Schutz, Y. Silva Loureiro, P. A. Soos, C. Stefanini, G. Swoboda, D. Tadel, M. and Taureg, H. Tavlet, M. Tissot-Daguette, P. de Matos, C. Torcato Vande Vyvre, P. Vanuxem, J. P. Aggarwal, M. M. and Bhati, A. K. Kumar, A. Sharma, M. Sood, G. Baldit, A. and Barret, V. Bastid, N. Blanchard, G. Castor, J. and Crochet, P. Daudon, F. Devaux, A. Dupieux, P. Force, P. and Grigoryan, S. Guerin, F. Guerin, F. Guernane, R. and Insa, C. Jouve, F. Lecoq, J. Manso, F. Rosnet, P. and Royer, L. Saturnini, P. Savinel, G. Humanic, T. J. and Kotov, I. V. Lisa, M. Nilsen, B. S. Truesdale, D. and Johnson, D. Bearden, I. Boggild, H. Christensen, C. H. and Gaardhoje, J. J. Gulbrandtsen, K. Nielsen, B. S. Renault, G. and Bartke, J. Gladysz-Dziadus, E. Kornas, E. Kowalski, M. and Rybicki, A. Wroblewski, A. Andronic, A. Antonczyk, D. and Badura, E. Bailhache, R. Berdermann, E. Braun-Munzinger, P. Busch, O. Ciobanu, M. Foka, P. Frankenfeld, U. and Garabatos, C. Gutbrod, H. Lippmann, C. Malzacher, P. and Marin, A. Miskowiec, D. Radomski, S. Schmidt, H. R. and Schwarz, K. Sedykh, K. Simon, R. S. Soyk, D. Stelzer, H. and Stockmeier, M. Tziledakis, G. Vranic, D. Wiechula, J. and Bonnes, U. Kraus, I. Oeschler, H. Appelshauser, H. and Blume, C. Dietel, T. Gazdzicki, M. Hartig, M. Kliemant, M. Kniege, S. Kolleger, T. Kramer, F. Lange, F. and Loizides, C. Ploskon, M. Renfordt, R. Sommer, W. Stock, R. Strobele, H. Berdnikov, Ya Ivanov, V Khanzadeev, A. and Miftakhov, N. Nicoulin, V. Polyakov, V. Rostchin, E. and Samsonov, V. Tarasenkova, O. Tarakanov, V. Zhalov, M. and Lopez Torres, E. Abrahantes Quintana, A. Diaz Valdes, R. and Angelov, T. Alt V. Cuveland, J. Gutfleish, M. Kalcher, S. and Lindenstruth, V. Panse, R. Reichling, C. Schneider, R. and Steinbeck, T. Troger, H. Tilsner G. Wiebalck, A. Adler, C. Emschermann, D. Glassel, P. Herrmann, N. Ludolphs, W. and Mahmoud, T. Mercado, J. Milosevic, J. Oyama, K. and Rusanov, I. Schnicker, R. Shukla, P. Soltveit, H. C. and Stachel, J. Vulpescu, B. Windelband, B. Yurevich, S. and Shigaki, K. Sugitate, T. Raniwala, S. Badyal, S. K. and Bala, R. Bhasin, A. Gupta, A. Gupta, V. K. Mahajan, S. and Mangotra, L. K. Potukuchi, B. V. K. S. Sambyal, S. S. and Akichine, P. G. Arefiev, V. A. Baatar, T. Batiounia, B. V. and Chepurnov, V. F. Chernenko, S. A. Dodokhov, V. K. and Fateev, O. V. Fedunov, A. G. Haiduc, M. Hasegun, D. and Kadychevsky, V. G. Kharadze, G. Khurelbaatar, B. and Koshurnikov, E. K. Lioubochits, V. C. Lobanov, V. I. and Malinina, L. V. Minaev, Y. I. Nioradze, M. Nomokonov, P. V. and Panebrattsev, Y. A. Penev, V. N. Pismennaya, V. G. and Pocheptsov, T. A. Roufanov, I. Shabratova, G. S. Shestakov, V. Shkloskaya, A. I. Sorin, A. S. Suleimanov, M. K. and Tevzadze, Y. Togoo, R. Vodopianov, A. S. Yurevich, V. I. and Zanevsky, Y. V. Zaporojets, S. A. Zinchenko, A. I. Aysto, J. and Bondila, M. Lyapin, V. Oinonen, M. Malkiewicz, T. and Ruuskanen, V. Seppanen, H. Trzaska, W. Yamaletkinov, S. and Jung, H. T. Jung, W. Kim, D. W. Kim, H. N. Kim, J. S. and Lee, K. S. Lee, S. C. Blank, T. Gemmeke, H. Bochek, G. L. Dovbnya, A. N. Kulibaba, V. I. Maslov, N. I. and Naumov, S. V. Ovchinnik, V. D. Potin, S. M. Starodubtsev, A. F. Borshchov, V. N. Chykalov, O. Kaurova, L. Kiprich, S. K. Klymova, L. Listratenko, O. M. Mykhylova, M. and Protenko, M. Reznik, O. Starkov, V. E. Kadenko, I. and Martynov, Y. Molodtsov, S. Sinyukov, Y. Zinovjev, G. and Bhattacharya, P. Bose, S. Chatterjee, S. Chattopadhyay, S. and Das, D. Das, I. Dutt-Mazumder, A. K. Majumdar, N. and Mukhopadhyay, S. Pal, S. Paul, L. Roy, P. Sanyal, A. and Sarkar, S. Sen, P. Sen, S. K. Sinha, B. C. Sinha, T. and Ahammed, Z. Bhaskar, P. Chattopadhyay, S. Das, D. Das, S. Majumdar, M. R. Dutta Ganti, M. S. Ghosh, P. Mohanty, B. Netrakanti, P. K. Pal, S. Singaraju, R. N. Singhal, V. Sinha, B. Viyogi, Y. P. Hartung, G. Krawutschke, T. and Ban, J. Bombara, M. Dirner, A. Hnatic, M. Kralik, I. and Kravcakova, A. Krivan, F. Krivda, M. Martinska, G. and Pastircak, B. Sandor, L. Urban, J. Vrlakova, J. and Cinausero, M. Fioretto, E. Prete, G. Ricci, R. A. and Vannucci, L. Branco, P. Carvalho, R. Seixas, J. Vilela Mendes, R. Oskarsson, A. Osterman, L. Otterlund, I. and Stenlund, E. A. Cheynis, B. Ducroux, L. Grossiord, J. Y. and Guichard, A. Pillot, P. Rapp, B. Tieulent, R. Molina, J. R. Alfaro Ayala, A. Moreno, E. Belmont Contreras, J. G. and Cuautle, E. D'Olivo, J. C. Dominguez, I. Flores, A. and Grabski, V. Corral, G. Herrera Linares, M. Martinez, M. I. and Martinez Davalos, A. Menchaca-Rocha, A. Montano Zetina, L. M. Nellen, L. Paic, G. del Pino, J. Reyes, P. and Sandoval, A. Vergara, S. Zepeda, A. Feshchenko, V. A. and Golubeva, M. B. Gorlychev, V. G. Guber, F. F. Karavichev, O. V. Karavicheva, T. L. Karpechev, E. V. Kurepin, A. B. and Maevskaya, A. I. Marin, V. V. Pshenichnov, I. A. Razin, V. I. Reshetin, A. I. Shileev, K. A. Topil'skaia, N. S. and Akindinov, A. N. Golovine, V. Kaidalov, A. B. Kats, M. M. and Kiselev, I. T. Kisselev, S. M. Lioublev, E. Martemianov, M. Martemiyanov, A. N. Polozov, P. A. Serov, V. S. and Smirnitski, A. V. Tchoumakov, M. M. Vetlitski, I. A. and Volochine, K. G. Vorobiev, L. S. Zagreev, B. V. Aleksandrov, D. Antonenko, V. Beliaev, S. Fokine, S. Ippolitov, M. and Karadjev, K. Koutcheriaev, I. Lebedev, V. Manko, V. I. and Moukhanova, T. Nianine, A. Nikolaev, S. Nikouline, S. and Patarakine, O. Peressounko, D. Sibiriak, I. Tsvetkov, A. and Vasiliev, A. Vinogradov, A. Yushmanov, I Grigoriev, V. A. Kaplin, V. A. Loginov, V. A. Nandi, B. K. Varma, R. and Chandratre, V. Kataria, V. Baumann, C. Glasow, R. and Gottschlag, H. Grosse-Oetringhaus, J. F. Heine, N. and Klein-Bosing, C. Reygers, K. Santo, R. Verhoeven, W. and Wessels, J. Wilk, A. Aphecetche, L. Berny, R. Bouvier, S. Conesa-Balbastre, G. Conesa-del-Valle, Z. Cussonneau, J. P. Delagrange, H. Dialinas, M. Finck, C. Erazmus, B. and Germain, M. Lefevre, F. Luquin, L. Martinez, G. Renard, C. Roy, C. Tournaire, A. Frolov, A. R. Pestov, I. N. and Awes, T. Cherney, M. Gorbunov, Y. Bimbot, L. Chambert, V. Charpy, A. Comets, M. P. Courtat, P. Drouet, S. and Edelbruck, P. Espagnon, B. Hfrivnacova, I. Kunne, R. Le Bornec, Y. Mac Cormick, M. Peyre, J. Pouthas, J. and Bravina, L. Lovhoiden, G. Skaali, B. Tveter, T. S. Vik, T. Antinori, F. Dainese, A. Dima, R. Fabris, D. and Faivre, J. Lunardon, M. Morando, M. Moretto, S. Pepato, A. Quercigh, E. Scarlassara, F. Segato, G. Turrisi, R. and Viesti, G. Choi, J. Beitlerova, A. Mares, J. Polak, K. Zavada, P. Petracek, V. Pachr, M. Skoda, L. and Bogolyubsky, M. Yu Khaoustov, G. V. Kharlov, Yu V. Minaev, N. G. Petrov, V. S. Polichtchouk, B. V. Sadovsky, S. A. and Senko, V. A. Soloviev, A. S. Stolpovsky, P. V. Victorov, V. A. Fernandez Tellez, A. Gamez Flores, E. Lopez-Ramirez, R. and Ortiz-Velczquez, A. Pagliarone, C. Roman-Lopez, S. and Tejeda-Munoz, G. Vargas, A. Villasenor Cendejas, L. Adamova, D. Kouchpil, S. Kouchpil, V. Kugler, A. Sumbera, M. and Wagner, V. Di Liberto, S. Mazzoni, M. A. Meddi, F. and Urciuoli, G. M. Cleymans, J. de Vaux, G. Fearick, R. W. and Szostak, A. Vilakazi, Z. Z. Anfreville, M. Baldisseri, A. and Becker, B. Borel, H. Castillo, J. Charvet, J. L. and Combet, M. Gosset, J. Hardy, P. Herlant, S. Orsini, F. and Penichot, Y. Pereira, H. Staley, F. M. Usseglio, M. and De Caro, A. De Gruttola, D. De Pasquale, S. Di Bartolomeo, A. Girard, M. Fusco Grella, G. Guarnaccia, C. Guida, M. and Romano, G. Sellitto, S. Silvestri, R. Virgili, T. and Basmanov, V. Budnikov, D. Demanov, V. Ianowski, V. and Ilkaev, R. Ivanov, A. Khlebnikov, A. Kouryakin, A. and Mikhailov, E. Nazarenko, S. Pavlov, V. Philchagin, S. and Punin, A. Punin, V. Poutevskoi, S. Rybin, A. Selin, I. and Smetanin, M. Telnov, A. Treskov, S. Vikhlyantsev, O. and Vinogradov, I Vyushin, A. Zavyalov, N. Zhelezov, S. and Zhitnik, A. Gotovac, S. Mudnic, E. Vidak, L. Asryan, A. G. Braun, M. A. Derkach, D. A. Feofilov, G. A. Igolkin, S. N. Ivanov, A. S. Kolevatov, R. S. Kolojvari, A. A. and Kondratiev, V. P. Naumenko, P. A. Toulina, T. A. Valiev, F. F. Vechernin, V. V. Vinogradov, L. I. Baudot, J. Bonnet, D. Coffin, J. P. Estienne, M. Hippolyte, B. Kuhn, C. and Lutz, J. R. Vernet, R. Hamagaki, H. Ozawa, K. Bonvicini, V. Borysov, O. Bosisio, L. Bregant, M. Camerini, P. and Contin, G. Faleschini, F. Fragiacomo, E. Grion, N. and Margagliotti, G. Piano, S. Rachevskaya, I. Rachevski, A. and Rui, R. Vacchi, A. Alessandro, B. Arnaldi, R. Bagnasco, S. Batigne, G. Beole, S. Bruna, E. Cerello, P. and Chiavassa, E. Cobanoglu, O. Coli, S. Crescio, E. De Marco, N. De Remigis, P. Ferretti, A. Gagliardi, M. and Gallio, M. Gaudichet, L. Gemme, R. Giraudo, G. and Giubellino, P. Idzik, M. Martoiu, S. Chiesa, A. Marzari and Masera, M. Mazza, G. Mereu, P. Monteno, M. Musso, A. and Oppedisano, C. Piccotti, A. Poggio, F. Prino, F. and Riccati, L. Rivetti, A. Scomparin, E. Stocco, D. and Tosello, F. Toscano, L. Travaglia, G. Vercellin, E. and Werbrouck, A. Wheadon, R. Yermia, F. Miake, Y. Esumi, S. and Buskop, J. J. F. De Haas, A. P. Ivan, C. Kamermans, R. and Mischke, A. Nooren, G. Oskamp, C. J. Peitzmann, Th. and Simili, E. Sokolov, O. Van Den Brink, A. Van Eijndhoven, N. and Enyo, H. Fujiwara, K. Kano, H. Onishi, H. Deloff, A. and Dobrowolski, T. Karpio, K. Malek, M. Malinowski, H. and Redlich, K. Siemiarczuk, T. Stefanek, G. Tykarski, L. and Wilk, G. Chajecki, Z. Gos, H. Janik, M. Jedynak, M. and Kisiel, A. Pawlak, T. J. Peryt, W. S. Pluta, J. and Skowronski, P. Slodkowski, M. Szuba, P. Traczyk, T. and Conner, E. S. Keidel, R. Cai, X. Ding, H. T. Liu, H. and Wang, X. R. Yang, H. Y. Yin, Z. B. Zhou, D. C. Cao, X. and Li, Q. Liu, Y. Z. Su, G. Tan, L. Zhu, G. X. and Atayan, M. Grigoryan, A. Gulkanyan, H. Harutyunyan, A. and Hayrapetyan, A. Kakoyan, V. Poghosyan, M. Sargsyan, G. and Anticic, T. Kadija, K. Susa, T. Arleo, F. Armesto, N. and Aurenche, P. Benhabib, L. Bogdanov, A. Borghini, N. and Carrer, N. Csorgo, T. Gupta, S. Heinz, U. W. Jacobs, P. M. Lednicky, R. Letessier, J. Mrowczynski, S. Rafelski, J. Ranft, J. Silvermyr, D. Wiedemann, U. A. Scapparone, E. ALICE Collaboration

Subjects
Nuclear Experiment
Abstract

ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark-gluon plasma in nucleus-nucleus collisions at the LHC. It currently involves more than 900 physicists and senior engineers, from both the nuclear and high-energy physics sectors, from over 90 institutions in about 30 countries. The ALICE detector is designed to cope with the highest particle multiplicities above those anticipated for Pb-Pb collisions (dN(ch)/dy up to 8000) and it will be operational at the start-up of the LHC. In addition to heavy systems, the ALICE Collaboration will study collisions of lower-mass ions, which are a means of varying the energy density, and protons (both pp and pA), which primarily provide reference data for the nucleus-nucleus collisions. In addition, the pp data will allow for a number of genuine pp physics studies. The detailed design of the different detector systems has been laid down in a number of Technical Design Reports issued between mid-1998 and the end of 2004. The experiment is currently under construction and will be ready for data taking with both proton and heavy-ion beams at the start-up of the LHC. Since the comprehensive information on detector and physics performance was last published in the ALICE Technical Proposal in 1996, the detector, as well as simulation, reconstruction and analysis software have undergone significant development. The Physics Performance Report (PPR) provides an updated and comprehensive summary of the performance of the various ALICE subsystems, including updates to the Technical Design Reports, as appropriate. The PPR is divided into two volumes. Volume I, published in 2004 (CERN/LHCC 2003-049, ALICE Collaboration 2004 J. Phys. G: Nucl. Part. Phys. 30 1517-1763), contains in four chapters a short theoretical overview and an extensive reference list concerning the physics topics of interest to ALICE, the experimental conditions at the LHC, a short summary and update of the subsystem designs, and a description of the offline framework and Monte Carlo event generators. The present volume, Volume II, contains the majority of the information relevant to the physics performance in proton-proton, proton-nucleus, and nucleus-nucleus collisions. Following an introductory overview, Chapter 5 describes the combined detector performance and the event reconstruction procedures, based on detailed simulations of the individual subsystems. Chapter 6 describes the analysis and physics reach for a representative sample of physics observables, from global event characteristics to hard processes.

Published
2006

36. πNandηpdeexcitation channels of theN*and Δ baryonic resonances between 1470 and 1680 MeV

Author

B. Tatischeff, M. P. Comets, Y. Le Bornec, M. MacCormick, P. Courtat, E. Loireleux, F. Reide, M. Boivin, R. Gacougnolle, and J. Yonnet

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Meson, 010308 nuclear & particles physics, Hadron, Particle Data Group, 01 natural sciences, Delta baryon, Baryon, Pion, 0103 physical sciences, Atomic physics, 010306 general physics, Dimensionless quantity
Abstract

Two reactions, pp{yields}ppX and pp{yields}p{pi}{sup +}X, are used to study the 1.47{

Published
2005

37. SPES4–$\pi$: installation for exclusive study of nuclear reactions

Author

J. L. Boyard, T. Hennino, L.G. Kudin, A.A. Zhdanov, A.N. Prokofiev, A. Maroni, E.M. Orischin, C. Gaarde, P. Courtat, P. Radvanyi, Liudmila Malinina, H.-P. Morsch, B. Ramstein, P. Zupranski, V. Poux, E. A. Strokovsky, B.G. Komkov, J. Larsen, M. Roy-Stephan, V.V. Golubev, M. Denoit, V.V. Baublis, M. Boivin, S.S. Volkov, J.-M. Martin, B.V. Razmyslovich, V.V. Astashin, V.Ya. Gerzenstein, A.V. Khanzadeev, C. Ellegaard, V.V. Vikhrov, I.I. Tkach, L. Farhi, R. Douet, S. Lebon, D. Bachelier, R. Skowron, A.V. Kravtsov, J.-F. Clavelin, An.A. Vorobyov, R.A. Kunne, I.B. Smirnov, V.L. Golovtsov, R. Gacougnolle, G.D. Alkhazov, V.A. Mylnikov, A.G. Atamanchuk, J.C. Jourdain, M. Österlund, W. Augustyniak, V.M. Samsonov, Institut de Physique Nucléaire d'Orsay (IPNO), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Spectrometer, Proton, 010308 nuclear & particles physics, Scattering, Physics::Instrumentation and Detectors, 29.40.-n, 29.30.-Aj, 07.05.Hd, Data acquisition, Particle detectors, Scintillator, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Baryon, Magnetic spectrometers, Pion, Dipole magnet, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Instrumentation
Abstract

EI SEP PHASE ACC; The paper describes the spectrometric system “SPES4–$\pi$” used at the National Laboratory Saturne (CE Saclay, France) for the exclusive study of the baryon resonance excitation in inelastic α and d scattering on the proton, as well as coherent pion production in charge exchange reactions. The system consists of the magnetic spectrometer SPES4 and two wide-aperture position-sensitive detector arrays, equipped with wire chambers and scintillator hodoscopes, installed around a large-gap C-shape dipole magnet.

Published
2005

38. Possible Indication of Narrow Baryonic Resonances Produced in the 1720-1790 MeV Mass Region

Author

P. Courtat, M. P. Comets, M. MacCormick, F. Reide, R. Gacougnolle, J. Yonnet, N. Willis, E. Loireleux, M. Boivin, B. Tatischeff, Y. Le Bornec, Institut de Physique Nucléaire d'Orsay (IPNO), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Physics, Particle physics, 010308 nuclear & particles physics, FOS: Physical sciences, General Physics and Astronomy, Exotic hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Invariant (physics), 01 natural sciences, Baryon, 0103 physical sciences, 12.40.Yx, 13.30.-a, 13.75.Cs, 14.20.Gk, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics
Abstract

Signals of two narrow structures at M=1747 MeV and 1772 MeV were observed in the invariant masses M_{pX} and M_{��^{+}X} of the pp->ppX and pp->p��^{+}X reactions respectively. Many tests were made to see if these structures could have been produced by experimental artefacts. Their small widths and the stability of the extracted masses lead us to conclude that these structures are genuine and may correspond to new exotic baryons. Several attempts to identify them, including the possible "missing baryons" approach, are discussed., 17 pages including 8 figures and 3 tables. ReVtex

Published
2004

39. Measurement of theH1(d→,pp)Xreaction and possible evidence for a structure atMpp=1945 MeV

Author

F. Hibou, P. Courtat, Y. Le Bornec, E. Loireleux, R. Gacougnolle, A.M. Bergdolt, B. Tatischeff, N. Willis, O. Bing, F. Reide, A. Moalem, G. Bergdolt, M.P. Combes-Comets, and M. Boivin

Subjects
Physics, Baryon, Nuclear reaction, Nuclear and High Energy Physics, Degree (graph theory), Hadron, Invariant mass, Elementary particle, Fermion, Atomic physics, Nucleon
Abstract

The analyzing powers of the {sup 1}H({ital {rvec d}},{ital pp}){ital X} reaction have been measured using polarized deuteron beams at {ital T}{sub {ital d}}=2.1 GeV, {theta}=17{degree} and {ital T}{sub {ital d}}=1.722 GeV, {theta}=0{degree}. In both cases a small oscillatory pattern has been observed in the tensor analyzing power at the same two-proton invariant mass and width {ital M}{sub {ital p}{ital p}}=1.945 GeV, {Gamma}{sub 1/2}{approx}8 MeV. The number of standard deviations are equal to 2.5 and 3.9, respectively.

Published
1992

40. ABCresonance in thep→p→ppX0reaction, or is theABCeffect made of colored quark cluster configurations?

Author

P. Courtat, F. Reide, M. P. Comets, M. Boivin, B. Tatischeff, R. Gacougnolle, J. Yonnet, N. Willis, Y. Le Bornec, and E. Loireleux

Subjects
Physics, Quark, Nuclear and High Energy Physics, Particle physics, Meson production, Cluster (physics), Resonance, Production (computer science), Atomic physics
Abstract

The reaction $\stackrel{\ensuremath{\rightarrow}}{p}\stackrel{\ensuremath{\rightarrow}}{p}\mathrm{ppX}$ was studied at two energies ${(T}_{p}=1520$ and 1805 MeV) and at several angles between $0\ifmmode^\circ\else\textdegree\fi{}$ and $17\ifmmode^\circ\else\textdegree\fi{}$ in the laboratory. The analyzing powers and cross sections of the $\mathrm{ABC}$ enhancement production were measured in the missing mass ${(M}_{{\ensuremath{\pi}}^{0}}l~{M}_{X}l~{M}_{\ensuremath{\eta}}).$ Several substructures were observed at different angles and both energies. Substructures at ${M}_{X}\ensuremath{\approx}310$ and 350 MeV were systematically extracted. Substructures in the higher mass range $400l~{M}_{X}l~500 \mathrm{MeV}$ were observed but their masses were less stable. These substructure masses have been associated with ${q}^{2}\ensuremath{-}{q}^{2}$ (and ${q}^{3}\ensuremath{-}{q}^{3})$ configurations, allowing a new assumption for the $\mathrm{ABC}$ effect description, as being colored multiquark clusters.

Published
2000

42. A vector and tensor polarimeter for high-energy deuterons

Author

L. B. Golovanov, J. L. Boyard, R.A. Kunne, Y. Bisson, J. Yonnet, E. A. Strokovsky, J. Ball, N.E. Cheung, C. F. Perdrisat, R. Gacougnolle, V.P. Ladygin, R. Skowron, L. Bimbot, N.M. Piskunov, E. Tomasi-Gustafsson, V. A. Punjabi, P. Courtat, I.M. Sitnik, T. Hennino, A.P. Tsvinev, Yu.T. Borzunov, M. Boivin, M. K. Jones, Robert, Suzanne, Institut de Physique Nucléaire d'Orsay (IPNO), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Elastic scattering, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Scattering, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, Monte Carlo method, Detector, Polarimeter, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Polarization (waves), Kinetic energy, 01 natural sciences, 7. Clean energy, Nuclear physics, Deuterium, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Instrumentation
Abstract

The characteristics of a polarimeter to measure the tensor polarization of deuterons with energy of a few GeV have been studied by Monte Carlo simulations. The analyzing reaction is forward elastic dp scattering. The results of the simulation have been verified with a prototype hydrogen cell and a recoil proton detector using drift tubes inserted in the polarimeter POMME. The test used a vector and tensor polarized deuteron beam of 1.6 GeV kinetic energy at the accelerator Saturne. The feasability of a vector and tensor deuteron high-energy polarimeter based on deuteron–proton elastic scattering reaction has been studied. We present here the prediction of a Monte Carlo simulation and the first results of a test made with a prototype, at the Saturne National Laboratory.

Published
1999

43. p⃗p⇒Δ[sup ++]Δ[sup 0], p⃗p⇒Δ[sup ++]n and p⃗p⇒pπ[sup +]X reactions at energies between 1.5 and 2.1 GeV

Author

R. Gacougnolle, M. P. Comets, J. Yonnet, N. Willis, B. Tatischeff, P. Courtat, F. Reide, Y. Le Bornec, E. Loireleux, and M. Boivin

Subjects
Baryon, Physics, Pion, Proton, Hadron, Analytical chemistry, Neutron, Atomic physics, Nucleon, Delta baryon, Dimensionless quantity
Abstract

The reaction pp→pπ+X has been studied at three energies (Tp=1520, 1805 and 2100 MeV), using the Saturne polarized proton beam and the SPES3 experimental facility. The analyzing powers of pp→Δ++Δ0, pp→Δ++n and pp→pπ+X reactions have been studied between 0° and 17° in the lab., which corresponds to an angular range between 0° and 100° (c.m.).

Published
1998

44. Subthreshold K+ production in deuteron and alpha induced nuclear reactions

Author

R. Wurzinger, P. Courtat, N. Willis, M. Dȩbowski, E. Schwab, M. Boivin, T. Kirchner, P. Koczon, E. Grosse, Y. Le Bornec, G. Wolf, R. Gacougnolle, B. Tatischeff, W. Waluś, Peter Senger, Andreas Wagner, J. Yonnet, S. Kabana, M. Mang, Robert, Suzanne, Institut de Physique Nucléaire d'Orsay (IPNO), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Projectile, Subthreshold conduction, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, 7. Clean energy, Nuclear physics, Deuterium, Yield (chemistry), 0103 physical sciences, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment, Beam (structure)
Abstract

Double differential cross sections d 2 σ/dpdΩ have been measured for π + and K + emitted around midrapidity in d + A and α + A collisions at a beam kinetic energy of 1.15 GeV/nucleon. The total π + yield increases by a factor of about 2 when using an alpha projectile instead of a deuteron whereas the K + yield increases by a factor of about 4. According to transport calculations, the K + enhancement depends both on the number of hadron-hadron collisions and on the energy available in those collisions: their center-of-mass energy increases with increasing number of projectile nucleons.

Published
1997

45. Subthreshold $K^+$ production in proton-nucleus collisions

Author

N. Willis, M. Debowski, B. Tatischeff, A. Zghiche, W. Waluś, E. Schwab, D. Miśkowiec, P. Courtat, M. Boivin, Peter Senger, R. Wurzinger, Y. Le Bornec, T. Kirchner, R. Barth, R. Gacougnolle, E. Grosse, C. Müntz, J. Yonnet, M. Cieślak, Andreas Wagner, M. P. Comets, C. Sturm, J. M. Martin, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Institut de Physique Nucléaire d'Orsay (IPNO), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Physics, Nuclear and High Energy Physics, Proton, Subthreshold conduction, 010308 nuclear & particles physics, 25.75.+r, 25.40.-h, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Momentum, medicine.anatomical_structure, 0103 physical sciences, medicine, Nuclear fusion, Spectral function, Atomic physics, Nucleon, 010306 general physics, Nuclear Experiment, Nucleus, Beam energy
Abstract

Double differential K$^+$ cross sections have been measured in p+C collisions at 1.2, 1.5 and 2.5 GeV beam energy and in p+Pb collisions at 1.2 and 1.5 GeV. The K$^+$ spectrum taken at 2.5 GeV can be reproduced quantitatively by a model calculation which takes into account first chance proton-nucleon collisions and internal momentum with energy distribution of nucleons according to the spectral function. At 1.2 and 1.5 GeV beam energy the K$^+$ data excess significantly the model predictions for first chance collisions. When taking secondary processes into account the results of the calculations are in much better agreement with the data.

Published
1996

46. Measurement of tensor polarization of deuterons from3He→d+pbreakup at internal momenta up to 0.4 GeV/c

Author

R.A. Kunne, E. A. Strokovsky, J. Yonnet, M Garçon, T. Hennino, R. Skowron, Yu.T. Borzunov, Y. Bisson, E. Tomasi-Gustafsson, N.M. Piskunov, I.M. Sitnik, J.-L. Sans, C. F. Perdrisat, J. L. Boyard, S. Nedev, L. B. Golovanov, J. Ball, P. Courtat, L. V. Malinina, M. Boivin, R. Gacougnolle, M. K. Jones, L. Bimbot, and V. A. Punjabi

Subjects
Physics, Nuclear reaction, History, Particle physics, Spectrometer, Solar energetic particles, Hadron, Polarization (waves), Computer Science Applications, Education, Nuclear physics, Baryon, Tensor, Nucleon
Abstract

The tensor polarization (?20) of deuterons emitted in the p(3He,d)X reaction at 0? in the lab. system was measured at the Saturne National Laboratory in Saclay, using the SPES-4 spectrometer with the HYPOM polarimeter in the area of its focal plane. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the 3He beam was varied from 4.60 to 5.66 GeV/c, thus providing a range of internal momenta k of the deuteron inside the 3He from 0 up to 0.4 GeV/c. The obtained data are compared with the theoretical predictions.

Published
2011

47. Measurement of the deuteron tensor polarization at the 3He → d + p vertex up to internal momenta of 0.43 GeV/c

Author

L. B. Golovanov, L. Bimbot, T. Hennino, Y. Bisson, R.A. Kunne, R. Skowron, J.-L. Sans, Di. Kirillov, Egle Tomasi-Gustafsson, N.M. Piskunov, L. V. Malinina, M. K. Jones, M. Boivin, V. A. Punjabi, S. Nedev, Yu.T. Borzunov, I.M. Sitnik, E. A. Strokovsky, L.S. Azhgirey, P. Courtat, C. F. Perdrisat, M. Garçon, M.P. Rekalo, J. P. Ball, R. Gacougnolle, J. Yonnet, and J. L. Boyard

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Angular momentum, Particle physics, Deuterium, Stress–energy tensor, Tensor, Beam emittance, Polarization (waves), Charged particle
Published
2000

48. Search for T=2 dibaryons in the p

Author

P. Courtat, A. Chisholm, F. Hibou, N. Willis, G. Bergdolt, R. Frascaria, A.M. Bergdolt, B. Tatischeff, M. Boivin, A. Moalem, F. Reide, O. Bing, M.P. Combes-Comets, Y. Le Bornec, E. Loireleux, D. Benabdelouahed, Elie Aslanides, P. Fassnacht, and C. Kerboul

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Degree (graph theory), Meson, Computer Science::Information Retrieval, Nuclear Theory, Hadron, Order (ring theory), Isospin, Bound state, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Energy (signal processing)
Abstract

In order to search for isospin-2 dibaryons and to study the inelastic nucleon-nucleon channels producing at least two pions, the differential cross sections and analyzing powers have been measured for the {ital p}({ital {rvec p}},{pi}{sup {minus}}){ital X} reaction with polarized proton beams of 1.45, 2.1, and 2.7 GeV. The pions were detected at an angle of 13.8{degree} by the SPESIII spectrometer located at Laboratoire National Saturne. No statistically significant evidence for structures corresponding to {pi}{ital NN} bound states or six-quark states could be established. However, upper limits to the cross section for such processes are deduced. The data analysis in terms of phase space has shown that as the bombarding energy increases, {ital N}{sup *}{ital N} final states have to be taken into account besides the usual {ital N}{Delta} and {Delta}{Delta} processes in order to adequately describe our results.

Published
1991

49. SEARCH FOR NARROW ISOVECTOR DIBARYONS CLOSE TO LOW MASSES THRESHOLD

Author

F. Hibou, N. Willis, Y. Le Bornec, E. Loireleux, A. Moalem, P. Courtat, F. Reide, A.M. Bergdolt, B. Tatischeff, G. Bergdolt, M. Boivin, O. Bing, M. P. Comets, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Quark, Physics, Meson, Isovector, Proton, General Engineering, Quantum number, Nuclear physics, Isospin, [PHYS.HIST]Physics [physics]/Physics archives, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Invariant mass, Nucleon, Nuclear Experiment
Abstract

For masses larger than 2 % + MT, narrow peaks in two proton invariant (missing) masses spectra : M (M ) are now well established. The existence of such PP x narrow peaks is not so unquestionable below 2 $ + Mr. Tensor analyzing power T20 + of the invariant mass M has been studied using the p(d,pp)~ reaction. Depending PP on the assumption done for background substraction -a hble or an oscillation mayappear at M = 1941 MeV. Additional data are under analysis and will improve the statistics. PP It is well known that narrow structures have been obsenred in two nucleon invariant masses, or missing mass experiments/l/. These structures have been tentatively attributed to isovector dibaryons although no proof has been advanced to associate them with quark degrees of freedom. This assumption relies only on the fact that such structures are not present in classical nuclear physics using meson exchanges and nucleon or delta degrees of freedom. The experimental certainty depends mainly on the quantum numbers and the mass of studied dibaryons. Up to now, none has been observed in T = 0/2/ or T = 2/31 isospin states. In case of T = 1 isospin, for the range of masses larger than 2 $ + M* (M > 2.016 GeV) there is a good agreement for narrow peaks between results obtained at Saturnel41 : measurement of d2a/dQdMx for 38e(p,d)~ reaction, and Lanpf/5/ where Ay was measured. These data correspond to the second generation of experiments, since they have used electronical detectors. ('1 Present address : Ben Gourion University of the Negev, P.O. Box 653 84105Beer Sheva, Israel. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1990631 C6-372 COLLOQUE DE PHYSIQUE Below 2.016 GeV, many structures have been presented, corresponding usually -but not alwaysto the first generation of experiments studying bubble chamber pictures. Here the masses of experimentally observed structures do not concentrate around a few values, but are more or less distributed from 2 % to 2 % + M?/1/. The necessity of a precise second generation experiment close to the two nucleon mass appears then naturally. 3 Such an experiment has been carried out at SATURNE with the p(d,pp)X reaction. Tensor polarized deuteron beam of 1.722 GeV has been used and the two protons detected at 0" using the SPES3 facility. The properties of the spectrometer : pmax/pmin z 2.5, and As2 = sr allow the study of the following two proton invariant mass range : 2 % < M < 1.963 GeV, PP the counting rate decreasing regularly from small to larger masses M . This result is mainPP ly due to pp FSI giving rise to a narrow maximum a few MeV above 2 M . Due to the granulaP rity of the detection, when two trajectories intercept a same scintillator of one among the two major trigger detection plans or give rise to two mixing tracks on the focal pla~e, the event is lost. This produces a loss of efficiency in the first three MeV of the spectra.This explains that our FSI is located around 1880.7 MeV, that is ?. 3 MeV higher than the peak maximum from low energy experiments. The detection has been described elsewhere/3/. The empty target accounts for about 5 % of the counting rate. The FWHM of the experimental wcdth for M is 1.2 MeV. The data have been therefore binned into 2 MeV intervals. The M hisPP PP togram presented in Fig. 1 is quite continuous, without any discontinuity having a number of standard deviations (S .D .) larger than 2.2. id = 1.722 GeV epp =0° 0.2 188

Published
1990

50. Near-threshold η production in the

Author

G. Bergdolt, M.P. Combes-Comets, F. Reide, Colin Wilkin, N. Willis, A.M. Bergdolt, B. Tatischeff, A. Moalem, R. Gacougnolle, Y. Le Bornec, O. Bing, A. Bouchakour, F. Hibou, M. Boivin, P. Courtat, F. Plouin, and F. Brochard

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Near threshold, Production (economics)
Published
2000

Catalog

Books, media, physical & digital resources
See catalog results