10,330 research outputs found
Weak Decays of Doubly Heavy Baryons: the case
Very recently, the LHCb collaboration has observed in the final state
a resonant structure that is identified as the
doubly-charmed baryon . Inspired by this observation, we
investigate the weak decays of doubly heavy baryons ,
, , ,
, , ,
and and focus on the decays into spin
baryons in this paper. At the quark level these decay processes are induced by
the or transitions, and the two spectator quarks can be
viewed as a scalar or axial vector diquark. We first derive the hadronic form
factors for these transitions in the light-front approach and then apply them
to predict the partial widths for the semi-leptonic and non-leptonic decays of
doubly heavy baryons. We find that a number of decay channels are sizable and
can be examined in future measurements at experimental facilities like LHC,
Belle II and CEPC.Comment: 40 pages, 4 figures, to appear in EPJ
Inverse Problem Approach for Non-Perturbative QCD: Foundation
We propose a novel theoretical framework to calculate the non-perturbative
QCD quantities. It starts from the dispersion relation of quantum field theory,
separating the high-energy and low-energy scales and using the known
perturbative theories to solve the unknown non-perturbative quantities by the
inverse problem. We prove that the inverse problem of dispersion relation is
ill-posed, with unique but unstable solutions. The regularization methods must
be used to get the stable approximate solutions. The method is based on the
strict mathematics, without any artificial assumptions. We have test some toy
models to vividly show the main features of the inverse problem. It can be
found that this approach can systematically improve the precision of the
solutions.Comment: 23 pages, 8 figure
Angular Reconstruction of a Lead Scintillating-Fiber Sandwiched Electromagnetic Calorimeter
A new method called Neighbor Cell Deposited Energy Ratio (NCDER) is proposed
to reconstruct incidence position in a single layer for a 3-dimensional imaging
electromagnetic calorimeter (ECAL).This method was applied to reconstruct the
ECAL test beam data for the Alpha Magnetic Spectrometer-02 (AMS-02). The
results show that this method can achieve an angular resolution of 7.36\pm 0.08
/ \sqrt(E) \oplus 0.28 \pm 0.02 degree in the determination of the photons
direction, which is much more precise than that obtained with the
commonly-adopted Center of Gravity(COG) method (8.4 \pm 0.1 /sqrt(E) \oplus
0.8\pm0.3 degree). Furthermore, since it uses only the properties of
electromagnetic showers, this new method could also be used for other type of
fine grain sampling calorimeters.Comment: 6 pages, 8 figure
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