Concept

Scalar meson

In high energy physics, a scalar meson is a meson with total spin 0 and even parity (usually noted as JP=0+). Compare to pseudoscalar meson. The first known scalar mesons have been observed since the late 1950s, with observations of numerous light states and heavier states proliferating since the 1980s. Scalar mesons are most often observed in proton-antiproton annihilation, radiative decays of vector mesons, and meson-meson scattering. The light (unflavored) scalar mesons may be divided into three groups: mesons having a mass below 1 GeV/c2 mesons having a mass between 1 GeV/c2 and 2 GeV/c2 other radially-excited unflavored scalar mesons above 2 GeV/c2 Since the late 1950s, the lightest scalar mesons were often interpreted within the framework of the linear sigma model, and many theorists still choose this interpretation of the scalar mesons as the chiral partners of the pseudoscalar meson multiplet. With the re-introduction of the σ meson as an acceptable candidate for a light scalar meson in 1996 by Tornqvist and Roos, in-depth studies into the lightest scalar mesons were conducted with renewed interest. Ever since Jaffe first suggested the existence of tetraquark multiplets in 1977, the lightest scalar mesons have been interpreted by some theorists to be possible tetraquark or meson-meson "molecule" states. The tetraquark interpretation works well with the MIT Bag Model of QCD, where the scalar tetraquarks are actually predicted to have lower mass than the conventional scalar mesons. This picture of the scalar mesons seems to fit experimental results well in certain ways, but often receives harsh criticism for ignoring unsolved problems with chiral symmetry breaking and the possibility of a non-trivial vacuum state as suggested by Gribov. Many attempts have been made to determine the quark content of the lighter scalar mesons; however, no consensus has yet been reached. In-depth studies of the unflavored scalar mesons began with the Crystal Ball and Crystal Barrel experiments of the mid 1990s, focusing on the mass range between 1 GeV/c2 and 2 GeV/c2.

About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Ontological neighbourhood
Related lectures (5)
Supersymmetry: Massless Multiplets and Chiral Multiplets
Explores massless and chiral multiplets in supersymmetry, quantum field algebra, and superspace structure.
Symmetries and Quark Model
Explores symmetries, quark model, meson construction, SU(3) flavor symmetry, baryon formation, and multiplet structures.
Show more
Related publications (54)

Search for the exotic decay of the Higgs boson into two light pseudoscalars with four photons in the final state in proton-proton collisions at √s=13 TeV

The nature of X(3872) from high-multiplicity pp collisions

Angelo Esposito

The structure of exotic resonances that do not trivially fit the usual quark model expectations has been a matter of intense scientific debate during the last two decades. A possible way of estimating the size of these states is to study their behavior whe ...
SPRINGER2021

Angular analysis of B0->D-Ds+ with Ds+-> Ds+gamma decays

Jian Wang, Lesya Shchutska, Olivier Schneider, Yiming Li, Yi Zhang, Aurelio Bay, Guido Haefeli, Christoph Frei, Frédéric Blanc, Tatsuya Nakada, Michel De Cian, François Fleuret, Elena Graverini, Renato Quagliani, Federico Betti, Andrea Merli, Aravindhan Venkateswaran, Vitalii Lisovskyi, Sebastian Schulte, Veronica Sølund Kirsebom, Elisabeth Maria Niel, Alexandre Brea Rodriguez, Ettore Zaffaroni, Mingkui Wang, Zhirui Xu, Chao Wang, Lei Zhang, Ho Ling Li, Mark Tobin, Minh Tâm Tran, Niko Neufeld, Matthew Needham, Maurizio Martinelli, Vladislav Balagura, Donal Patrick Hill, Liang Sun, Xiaoxue Han, Liupan An, Federico Leo Redi, Maxime Schubiger, Hang Yin, Violaine Bellée, Preema Rennee Pais, Pavol Stefko, Tara Nanut, Maria Elena Stramaglia, Yao Zhou, Tommaso Colombo, Vladimir Macko, Guillaume Max Pietrzyk, Evgenii Shmanin, Maxim Karpov, Simone Meloni, Xiaoqing Zhou, Surapat Ek-In, Carina Trippl, Sara Celani, Marco Guarise, Serhii Cholak, Dipanwita Dutta, Zheng Wang, Yong Yang, Yi Wang, Hao Liu, Hans Dijkstra, Gerhard Raven, Peter Clarke, Frédéric Teubert, Giovanni Carboni, Victor Coco, Shuai Liu, Adam Davis, Paolo Durante, Yu Zheng, Renjie Wang, Anton Petrov, Maxim Borisyak, Feng Jiang, Chen Chen, Alexey Boldyrev, Almagul Kondybayeva, Hossein Afsharnia

The first full angular analysis of the B0 -> D-Ds+ decay is performed using 6 fb(-1) of pp collision data collected with the LHCb experiment at a centre-of-mass energy of 13 TeV. The Ds+-> Ds+gamma and D*- -> D0- vector meson decays ar ...
SPRINGER2021
Show more
Related concepts (5)
Pseudoscalar meson
In high-energy physics, a pseudoscalar meson is a meson with total spin 0 and odd parity (usually notated as J^P = 0^− ). Pseudoscalar mesons are commonly seen in proton-proton scattering and proton-antiproton annihilation, and include the pion (π), kaon (K), eta (η), and eta prime () particles, whose masses are known with great precision. Among all of the mesons known to exist, in some sense, the pseudoscalars are the most well studied and understood.
Vector meson
In high energy physics, a vector meson is a meson with total spin 1 and odd parity (usually noted as JP = 1−). Vector mesons have been seen in experiments since the 1960s, and are well known for their spectroscopic pattern of masses. The vector mesons contrast with the pseudovector mesons, which also have a total spin 1 but instead have even parity. The vector and pseudovector mesons are also dissimilar in that the spectroscopy of vector mesons tends to show nearly pure states of constituent quark flavors, whereas pseudovector mesons and scalar mesons tend to be expressed as composites of mixed states.
Pseudovector meson
In high energy physics, a pseudovector meson or axial vector meson is a meson with total spin 1 and even parity (+) (usually noted as J^ P = 1^+ ). Compare to a vector meson, which has a total spin 1 and odd parity (that is, J^ P = 1^− ). The known pseudovector mesons fall into two different classes, all have even spatial parity ( P = "+" ), but they differ in another kind of parity called charge parity (C) which can be either even (+) or odd (−).
Show more