221 research outputs found
Evidence for a new resonance with in the old data of reaction
Distinctive patterns are predicted by quenched quark models and unquenched
quark models for the lowest SU(3) baryon nonet with spin parity .
While the quenched quark models predict the lowest resonance
to be above 1600 MeV, the unquenched quark models predict it to be around
energy. Here we re-examine some old data of the \kp \to \la
reaction and find that besides the well established with
, there is indeed some evidence for the possible existence of a new
resonance with around the same mass but with broader
decay width. Higher statistic data on relevant reactions are needed to clarify
the situation.Comment: 7 pages, 4 figure
Proposal and theoretical formalism for studying baryon radiative decays from J/\psi \to B^*\bar B + \bar{B^*}B \to \gamma B\bar B
With accumulation of high statistics data at BESIII, one may study many new
interesting channels. Among them, J/\psi \to B^*\bar B + \bar{B^*}B \to \gamma
B\bar B processes may provide valuable information of the radiative decays of
the excited baryons (N^*,\Lambda^*,\Sigma^*,\Xi^*), and may shed light on their
internal quark-gluon structure. Our estimation for the branching ratios of the
nucleon excitations N^*(1440), N^*(1535) and N^*(1520) from the reaction J/\psi
\to N^*\bar p + \bar N^* p \to \gamma p\bar p, indicates that these processes
can be studied at BESIII with 10^{10} J/\psi events. Explicit theoretical
formulae for the partial wave analysis (PWA) of the J/\psi \to B^*\bar B +\bar
B^* B with B^*\to B \gamma and \bar B^*\to \bar B\gamma within covariant L-S
Scheme are provided.Comment: 25 page
Harmonic oscillator in a background magnetic field in noncommutative quantum phase-space
We solve explicitly the two-dimensional harmonic oscillator and the harmonic
oscillator in a background magnetic field in noncommutative phase-space without
making use of any type of representation. A key observation that we make is
that for a specific choice of the noncommutative parameters, the time reversal
symmetry of the systems get restored since the energy spectrum becomes
degenerate. This is in contrast to the noncommutative configuration space where
the time reversal symmetry of the harmonic oscillator is always broken.Comment: 7 pages Late
Predicting Kidney Transplant Survival using Multiple Feature Representations for HLAs
Kidney transplantation can significantly enhance living standards for people
suffering from end-stage renal disease. A significant factor that affects graft
survival time (the time until the transplant fails and the patient requires
another transplant) for kidney transplantation is the compatibility of the
Human Leukocyte Antigens (HLAs) between the donor and recipient. In this paper,
we propose new biologically-relevant feature representations for incorporating
HLA information into machine learning-based survival analysis algorithms. We
evaluate our proposed HLA feature representations on a database of over 100,000
transplants and find that they improve prediction accuracy by about 1%, modest
at the patient level but potentially significant at a societal level. Accurate
prediction of survival times can improve transplant survival outcomes, enabling
better allocation of donors to recipients and reducing the number of
re-transplants due to graft failure with poorly matched donors
and colliding in noncommutative space
By studying the scattering process of scalar particle pion on the
noncommutative scalar quantum electrodynamics, the non-commutative amendment of
differential scattering cross-section is found, which is dependent of
polar-angle and the results are significantly different from that in the
commutative scalar quantum electrodynamics, particularly when . The non-commutativity of space is expected to be explored at around
TeV.Comment: Latex, 12 page
Prompt atmospheric neutrino fluxes: perturbative QCD models and nuclear effects
We evaluate the prompt atmospheric neutrino flux at high energies using three
different frameworks for calculating the heavy quark production cross section
in QCD: NLO perturbative QCD, factorization including low-
resummation, and the dipole model including parton saturation. We use QCD
parameters, the value for the charm quark mass and the range for the
factorization and renormalization scales that provide the best description of
the total charm cross section measured at fixed target experiments, at RHIC and
at LHC. Using these parameters we calculate differential cross sections for
charm and bottom production and compare with the latest data on forward charm
meson production from LHCb at TeV and at TeV, finding good agreement
with the data. In addition, we investigate the role of nuclear shadowing by
including nuclear parton distribution functions (PDF) for the target air
nucleus using two different nuclear PDF schemes. Depending on the scheme used,
we find the reduction of the flux due to nuclear effects varies from to
at the highest energies. Finally, we compare our results with the
IceCube limit on the prompt neutrino flux, which is already providing valuable
information about some of the QCD models.Comment: 61 pages, 25 figures, 11 table
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