417 research outputs found
Branching Ratios for the Decay of
Based on measurements the branching ratios for the decay of the recently
discovered dibaryon resonance into two-pion production channels and
into the channel are evaluated. Possibilities for a decay into the
isoscalar single-pion channel are discussed. Finally also the electromagnetic
decay of is considered
Examination of the Nature of the ABC Effect
Recently it has been shown by exclusive and kinematically complete
experiments that the appearance of a narrow resonance structure in
double-pionic fusion reactions is strictly correlated with the appearance of
the so-called ABC effect, which denotes a pronounced low-mass enhancement in
the -invariant mass spectrum. Whereas the resonance structure got its
explanation by the dibaryonic resonance, a satisfactory explanation
for the ABC effect is still pending. In this paper we discuss possible
explanations of the ABC effect and their consequences for the internal
structure of the dibaryon
Novel Six-Quark Hidden-Color Dibaryon States in QCD
The recent observation of a hadronic resonance in the proton-neutron
system with isospin and spin-parity raises the possibility
of producing other novel six-quark dibaryon configurations allowed by QCD. A
dramatic example of an exotic six-quark color-singlet system is the charge
, isospin I=3, state which couples strongly to
+ The width and decay properties of such
six-quark resonances could be regarded as manifestations of "hidden-color"
six-quark configurations, a first-principle prediction of QCD -- SU(3)-color
gauge theory for the deuteron distribution amplitude. Other implications and
possible future experiments are discussed
On Sequential Single-Pion Production in Double-Pionic Fusion
Recently a two-step process has been proposed for the double-pionic fusion to
deuterium , which is solely based on total cross
section data for the two sequential single-pion production steps followed by . Though this sequential process was aimed
to explain the dibaryon resonance peak in double-pionic fusion, we
demonstrate that this is not the case. It rather fits to a possible broad bump
at 2.31 GeV in the energy dependence of the reaction,
which was recently interpreted as a consequence of dibaryonic excitations in
isoscalar single-pion production
A new possibility for light-quark Dark Matter
Despite many decades of study the physical origin of "dark matter" in the Universe remains elusive. In this letter we calculate the properties of a completely new dark matter candidate - Bose-Einstein condensates formed from a recently discovered bosonic particle in the light-quark sector, the hexaquark. In this first study, we show stable Bose-Einstein condensates could form in the primordial early universe, with a production rate sufficiently large that they are a plausible new candidate for dark matter. Some possible astronomical signatures of such dark matter are also presented
Strange Hadron Spectroscopy with a Secondary KL Beam at GlueX
We propose to create a secondary beam of neutral kaons in Hall D at Jefferson
Lab to be used with the GlueX experimental setup for strange hadron
spectroscopy. A flux on the order of 3 x 10^4 KL/s will allow a broad range of
measurements to be made by improving the statistics of previous data obtained
on hydrogen targets by three orders of magnitude. Use of a deuteron target will
provide first measurements on the neutron which is {\it terra incognita}.
The experiment will measure both differential cross sections and
self-analyzed polarizations of the produced {\Lambda}, {\Sigma}, {\Xi}, and
{\Omega} hyperons using the GlueX detector at the Jefferson Lab Hall D. The
measurements will span c.m. cos{\theta} from -0.95 to 0.95 in the c.m. range
above W = 1490 MeV and up to 3500 MeV. These new GlueX data will greatly
constrain partial-wave analyses and reduce model-dependent uncertainties in the
extraction of strange resonance properties (including pole positions), and
provide a new benchmark for comparisons with QCD-inspired models and lattice
QCD calculations.
The proposed facility will also have an impact in the strange meson sector by
providing measurements of the final-state K{\pi} system from threshold up to 2
GeV invariant mass to establish and improve on the pole positions and widths of
all K*(K{\pi}) P-wave states as well as for the S-wave scalar meson
{\kappa}(800).Comment: 97 pages, 63 figures, Proposal for JLab PAC45, PR12-17-001; v3 missed
citation in Sec 9 (pg 22
The d*(2380) in neutron stars - a new degree of freedom?
Elucidating the appropriate microscopic degrees of freedom within neutron stars remains an open question which impacts nuclear physics, particle physics and astrophysics. The recent discovery of the first non-trivial dibaryon, the d∗(2380), provides a new candidate for an exotic degree of freedom in the nuclear equation of state at high matter densities. In this paper a first calculation of the role of the d∗(2380) in neutron stars is performed, based on a relativistic mean field description of the nucleonic degrees of freedom supplemented by a free boson gas of d∗(2380). The calculations indicate that the d∗(2380) would appear at densities around three times normal nuclear matter saturation density, influencing the upper mass limit for a stable neutron star and the neutron and proton fractions. New possibilities for neutron star cooling mechanisms arising from the d∗(2380)are also predicted
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