Jean-Marc Richard - Academia.edu (original) (raw)

Papers by Jean-Marc Richard

Few-Body Systems, 2013

We review some recent studies on the string model of confinement inspired by the strong-coupling ... more We review some recent studies on the string model of confinement inspired by the strong-coupling regime of QCD and its application to exotic multiquark configurations. This includes two quarks and two antiquarks, four quarks and one antiquark, six quarks, and three quarks and three antiquarks with a careful treatment of the corresponding few-body problem.

Physics Letters B, Feb 1, 1991

Few-body Systems, Jan 3, 2013

Physics Letters B, Apr 1, 1979

A recent derivation of the hyperfine quadrupole moment of the orthomuonium is revisited. Expressi... more A recent derivation of the hyperfine quadrupole moment of the orthomuonium is revisited. Expressions are given for the orbital admixture in the first levels. These orbital mixings are also computed by an approximate numerical method which can be useful for the phenomenology of quarkonium systems in potential models.

arXiv (Cornell University), May 5, 2022

A review is presented of the antinucleon-nucleon interaction, and some related issues such as fun... more A review is presented of the antinucleon-nucleon interaction, and some related issues such as fundamental symmetries, annihilation mechanisms, antinucleonnucleus scattering, antiprotonic atoms and neutron-antineutron oscillations. The overall perspective is historical but the modern approaches are also presented.

Springer eBooks, 1990

Edited by F. Bradamante, J.-M. Richard, and R. Klapisch A Continuation Order Plan is available fo... more Edited by F. Bradamante, J.-M. Richard, and R. Klapisch A Continuation Order Plan is available for this series. A continuation order will bring delivery of each new volume immediately upon publication. Volumes are billed only upon actual shipment. For further information please contact the publisher.

Journal of Physics G: Nuclear and Particle Physics, 2021

The violation of baryon number, B , is an essential ingredient for the preferential creation of m... more The violation of baryon number, B , is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron–antineutron oscillation ( n → n ̄ ) via mixing, neutron–antineutron oscillation via regeneration from a sterile neutron state ( n → [ n ′ , n ̄ ′ ] → n ̄ ), and neutron disappearance (n → n′); the effective Δ B = 0 process of neutron regeneration ( n → [ n ′ , n ̄ ′ ] → n ) is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryog...

Physics Letters B, 1979

Abstract We discuss the effect of fourth-order QCD corrections to the spin dependent potential be... more Abstract We discuss the effect of fourth-order QCD corrections to the spin dependent potential between heavy quark and antiquark.

Few-Body Systems, 1993

... We would like to give special thanks to Mrs. Colette Suter, the Workshop Secretary, who took ... more ... We would like to give special thanks to Mrs. Colette Suter, the Workshop Secretary, who took charge of the practical administration and the smooth coordination of all the side, but ... Raimondo Bertini, [20], [213, Laboratoire National Saturne, CEN Saclay Dr. Jaume Carbonell, Prof. ...

Séminaire de théorie spectrale et géométrie, 1989

Ordre des niveaux des systèmes quark-antiquark et des systèmes de 3 quarks Séminaire de Théorie s... more Ordre des niveaux des systèmes quark-antiquark et des systèmes de 3 quarks Séminaire de Théorie spectrale et géométrie, tome 7 (1988-1989), p. 31-32 <http://www.numdam.org/item?id=TSG_1988-1989__7__31_0> © Séminaire de Théorie spectrale et géométrie (Chambéry-Grenoble), 1988-1989, tous droits réservés. L'accès aux archives de la revue « Séminaire de Théorie spectrale et géométrie » implique l'accord avec les conditions générales d'utilisation (http://www.numdam.org/legal.php). Toute utilisation commerciale ou impression systématique est constitutive d'une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright. Article numérisé dans le cadre du programme Numérisation de documents anciens mathématiques http://www.numdam.org/ Séminaire de théorie spectrale et géométrie CHAMBÉRY-GRENOBLE 1988-1989(31-32) ORDRE DES NIVEAUX DES SYSTEMES QUÀRK-ÀNTIQUÀRK ET DES SYSTÈMES DE 3 QUARKS par Jean-Marc RICHARD

We have studied, using double ratio of QCD (spectral) sum rules, the ratio between the masses of ... more We have studied, using double ratio of QCD (spectral) sum rules, the ratio between the masses of T cc and X(3872) assuming that they are respectively described by the D − D * and D −D * molecular currents. We found (within our approximation) that the masses of these two states are almost degenerate. Since the pion exchange interaction between these mesons is exactly the same, we conclude that if the observed X(3872) meson is a DD * + c.c. molecule, then the DD * molecule should also exist with approximately the same mass. An extension of the analysis to the b-quark case leads to the same conclusion. We also study the SU(3) breakings for the T s QQ /T QQ mass ratios. Motivated by the recent Belle observation of two Z b states, we revise our determination of X b by combining results from exponential and FESR sum rules.

Physics at LEAR with Low-Energy Cooled Antiprotons, 1984

Measurement of the polarization in pp elastic scattering is planned in the near future at LEAR1).... more Measurement of the polarization in pp elastic scattering is planned in the near future at LEAR1). Hopefully, polarized target and polarized beam facilities will enlarge the field of spin physics for the second and third generation of experiments. In this short review, I will try to present the status of the art on spin effects in potential models.

Nuclear Physics B, 1979

ABSTRACT

Journal of Physics A: Mathematical and Theoretical, 2011

We study the behavior of energy levels in two dimensions for exotic atoms, i.e., when a long-rang... more We study the behavior of energy levels in two dimensions for exotic atoms, i.e., when a long-range attractive potential is supplemented by a short-range interaction, and compare the results with these of the one-and three-dimensional cases. The energy shifts are well reproduced by a scattering length formula δE = A 2 0 / ln(a/R), where a is the scattering length in the short-range potential, A 2 0 /(2 π) the square of the wave function at the origin in the external potential, and R is related to the derivative with respect to the energy of the solution that is regular at large distances.

Few-Body Systems, 1995

. We study the stability and the properties of the ground state of neutral systems containing u... more . We study the stability and the properties of the ground state of neutral systems containing up to four positively charged bosons and their antiparticles. Examples are the di-pionium molecule (π + π −)2, which is almost identical to the positronium molecule (e + e −)2, the tri-pionium (π + π −)3, and the quadri-pionium (π + π −)4 molecules.

Physical review, Jan 22, 2001

We derive a new lower bound for the ground state energy E F (N, S) of N fermions with total spin ... more We derive a new lower bound for the ground state energy E F (N, S) of N fermions with total spin S in terms of binding energies E F (N −1, S ±1/2) of (N −1) fermions. Numerical examples are provided for some simple short-range or confining potentials.

Springer Proceedings in Physics, 2020

In this contribution we discuss the adequate treatment of the 4− and 5−body dynamics within a con... more In this contribution we discuss the adequate treatment of the 4− and 5−body dynamics within a constituent quark framework. We stress that the variational and Born-Oppenheimer approximations give energies rather close to the exact ones, while the diquark approximation might be rather misleading. Hall-Post inequalities provide very useful lower bounds that exclude possible stable states for some mass ratios and color wave functions.