scholarly journals SIGNATURES OF EXOTIC HADRONS

2011 ◽  
Vol 26 (29) ◽  
pp. 4855-4879
Author(s):  
FRANCESCO RENGA

Hadron spectroscopy represented in the past a major tool for understanding the fundamental symmetries of strong forces. More recently, the interest on this topic has been revitalized by the discovery of new quarkonium-like resonances, that do not fit in the standard picture and whose understanding could improve our mastery of quantum chromodynamics. I review here the experimental signatures of these exotic hadrons, at present and future e+e- and hadron collider experiments.

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Zhiqing Liu

AbstractIn 1964, both Gell-Mann and Zweig proposed the famous Quark Model in particle physics, which tells us hadrons are built of three quarks (baryons) or quark anti-quark pair (mesons). However, the theory of strong interaction—QCD—allows the existing of hadrons beyond the conventional baryon and meson picture. These new hadron states are called exotic hadrons, and have been searched for over the past half century. In this review, I will introduce you the discovery of a new particle called Zc(3900), which is considered as the first convincing four-quark particle. The observation of four-quark matter gains great interest in particle physics, and triggered subsequent intensive study of exotic hadrons, which brings us to a new era of hadron spectroscopy and refreshes our knowledge about the hadronic matter in our universe.


2018 ◽  
Vol 46 ◽  
pp. 1860005
Author(s):  
Chengping Shen ◽  
Suxian Li

Since the invention of the quark model in 1964 hadrons are formed from a quark-antiquark pair called mesons or three quarks called baryons. However, QCD-motivated models for hadrons predict more complex structures on the hadrons components called generically exotics. These include tetraquark, pentaquark, the six-quark H-dibaryon, hybrid, and glueball mesons. Exotic hadrons have been systematically searched for in many experiments and studied in theories. In the past decade, lots of new hadrons that cannot fit into the normal mesons or baryons were discovered, the so-called [Formula: see text] states. Even so, no unambiguous candidates for any of those exotic configurations have been identified. This review presents an overview of the remarkable progress in the field of exotic hadrons over the past few years.


2018 ◽  
Vol 175 ◽  
pp. 01022 ◽  
Author(s):  
Zohreh Davoudi

Explorations of the properties of light nuclear systems beyond their lowestlying spectra have begun with Lattice Quantum Chromodynamics. While progress has been made in the past year in pursuing calculations with physical quark masses, studies of the simplest nuclear matrix elements and nuclear reactions at heavier quark masses have been conducted, and several interesting results have been obtained. A community effort has been devoted to investigate the impact of such Quantum Chromodynamics input on the nuclear many-body calculations. Systems involving hyperons and their interactions have been the focus of intense investigations in the field, with new results and deeper insights emerging. While the validity of some of the previous multi-nucleon studies has been questioned during the past year, controversy remains as whether such concerns are relevant to a given result. In an effort to summarize the newest developments in the field, this talk will touch on most of these topics.


2005 ◽  
Vol 20 (22) ◽  
pp. 5234-5243
Author(s):  
W. J. STIRLING

Quantum Chromodynamics is an established part of the Standard Model and an essential part of the toolkit for searching for new physics at high-energy colliders. I present a status report on the theory of QCD and review some of the important developments in the past year.


1994 ◽  
Vol 05 (02) ◽  
pp. 195-200
Author(s):  
CARLETON DeTAR

Through numerical simulations over the past decade we have made significant progress toward solving quantum chromodynamics (QCD), the widely accepted theory of the strong interactions. Quantitatively respectable results are beginning to emerge. We are also gaining new qualitative insights into the workings of the theory that will assist in the design and analysis of experiment. I give a few examples of recent progress in lattice QCD and discuss goals and prospects for computations using the coming generation of teraflops-scale supercomputers.


Author(s):  
AMÉLIE KUHRT

This chapter examines how an historian of the ancient Near East sets about reconstructing a picture of the past using material of great diversity in terms of type and historical value. It demonstrates this approach by considering the figure of the Achaemenid king, Cyrus II ‘the Great’ of Persia. The discussion begins by creating a conventional image of the king and consolidating it. It then analyses the evidence that has been used to strengthen the picture and presents some historical realities. The basis for the standard picture of Cyrus the Great is provided by material in classical writers and the Old Testament. Cyrus introduced a new policy of religious toleration together with active support for local cults, exemplified by the permission he granted to the Jewish exiles to return to Jerusalem and rebuild their temple, with generous funding from central government. The chapter also considers the date for Cyrus' defeat of the Median king Astyages (550), as well as his conquest of Babylon itself.


2016 ◽  
Vol 31 (38) ◽  
pp. 1650209
Author(s):  
Qin Chang ◽  
Yunyun Zhang ◽  
Lin Han

Motivated by the heavy-flavor experiments at running Large Hadron Collider (LHC) and upgrading SuperKEKB, which provide abundant [Formula: see text] data samples, the tree-dominated [Formula: see text] and [Formula: see text] (n =1, 2, 3) weak decays are studied within the framework of quantum chromodynamics (QCD) factorization. The QCD corrections to the longitudinal and transverse amplitudes are evaluated at next-to-leading order, and the branching fractions and polarization fractions are predicted. Numerically, the [Formula: see text] decays have relatively large branching fractions at the order of [Formula: see text] and are in the scope of the LHC and SuperKEKB/Belle-II experiments.


2017 ◽  
Vol 72 (6) ◽  
pp. 493-525 ◽  
Author(s):  
Jochem Hauser ◽  
Walter Dröscher

AbstractThis article provides a review of the latest experimental results in quantum physics and astrophysics, discussing their repercussions on the advanced physical theories that go beyond both the SMs (standard models) of particle physics and cosmology. It will be shown that many of the essential concepts of the advanced theoretical models developed over the past 40 years are no longer tenable because they are contradicting the novel data. Most recent results (December 2016) from the Large Hadron Collider revealed no new matter particles up to particle masses of 1.6 TeV/c2, which is in accordance with recent ACME experimental data (2014) that saw no electric dipole moment for the electron as predicted by these theories. Moreover, the LUX experiment (since 2013) did not see any dark matter particles either, thus independently supporting LHC and ACME measurements. Furthermore, experimental particle physics seems to be telling us that dark matter particles (LHC results) do not exist, suggesting that dark matter particles either are more exotic or are more difficult to detect than had been predicted in the past decades (less likely with recent LHC results). Astrophysical observations since 1933, starting with Caltech astronomer Zwicky, however, have provided irrefutable evidence for the existence of dark matter, for instance, based on the phenomenon of gravitational lensing as well as observed rotational velocities of stars orbiting the galactic center that are deviating from Newton’s law. Surprisingly, recent astronomical observations by Bidin, ESO (2010, 2012, 2014), seem to indicate the absence of dark matter within galaxies. In addition, cosmology at present has no explanation for about 68 % of the energy in the Universe that comes in the form of dark energy. Recently, measured data from three entirely different types of experiments both on earth and in space (2006–2011) are hinting at completely novel features of gravity that, if confirmed, must be outside Einstein’s general relativity. Extreme gravitomagnetic and gravity-like fields may have been observed at cryogenic temperatures generated by a rotating ring or disk. However, these experimental results are not conclusive so far. The strength of these extreme fields has been calculated and, according to the respective equations, should be sufficient to serve as a basis for a gravitational technology that, for example, could establish long sought field propulsion (i.e. propulsion without fuel), actively researched by physicists and rocket engineers in the 1960s and 1990s. This article concludes with an outlook on the novel technology of gravitational engineering that might follow from gravity-like fields and discusses the novel physical concepts resulting from the existence of these extreme gravitomagnetic fields.


2006 ◽  
Vol 84 (5) ◽  
pp. 411-418
Author(s):  
H Jeremie ◽  
P Leblanc ◽  
E Lefebvre

The angular correlations of four-jet events from hadronic decays of the Z0 have been studied in the past mainly to extract from them the fundamental constants of quantum chromodynamics called colour factors. Previous studies have used all the available phase-space in order to maximize statistics. In this note we want to point out the possibility that significant differences between experiment and theory in restricted regions of phase space might have escaped detection. Such differences could be a harbinger of the existence of new particles. Some preliminary results are presented.


2018 ◽  
Vol 181 ◽  
pp. 01022 ◽  
Author(s):  
Todd K. Pedlar

The Belle II experiment, being constructed at the KEK laboratory in Japan, represents a substantial upgrade of both the Belle detector and the KEKB accelerator. It is expected that Belle II will collect 50 times more data than existing B-Factory samples beginning in 2019. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now number in the dozens, and represent the emergence of a new category within Quantum Chromodynamics. In this article we summarize the capabilities of Belle II to explore both exotic and conventional bottomonium physics, with a particular focus on the physics reach of the first data, where opportunities exist to make an immediate impact in this area.


Sign in / Sign up

Export Citation Format

Share Document