31,179 research outputs found
An Effective Cutoff for the Isolalated Lepton Background from Bottom Decay --
There is a strong correlation between the and isolation of the lepton
coming from decay. Consequently the isolated lepton background from
decay goes down rapidly with increasing lepton ; and there is a
cutoff beyond which it effectively vanishes. For the isolation cut of GeV, appropriate for LHC, the lepton cutoff is 80 GeV. This can be
exploited to effectively eliminate the background from the like sign
dilepton channel apropriate for Majorana particle searches, as well as the
unlike sign dilepton and the single lepton channels appropriate for the top
quark search. We illustrate this with a detailed analysis of the background
in these channels along with the signals at LHC energy using both parton level
MC and ISAJET programs.Comment: TIFR/TH/93-23 (LATEX, 20 pages, 7 figures available on request
Isobaric incompressibility of the isospin asymmetric nuclear matter
The isospin dependence of the saturation properties of asymmetric nuclear
matter, particularly the incompressibility at saturation density is systematically studied using density
dependent M3Y interaction. The characterizes the isospin dependence of
the incompressibility at saturation density . The approximate
expression is often used for where
and represent, respectively, the slope and curvature parameters of
the symmetry energy at . It can be expressed accurately as
where is the third-order
derivative parameter of symmetric nuclear matter at . The results of
this addendum to Phys. Rev. C 80, 011305(R) (2009) indicate that the
contribution to is not insignificant.Comment: 4 pages including 1 table and 1 figur
A Mass Formula from Light to Hypernuclei
Simultaneous description of ordinary and hypernuclei masses by a single mass
formula has been a great challenge in nuclear physics. Hyperon-separation
energies of about forty Lambda(), three
Lambda-Lambda(), one Sigma() and seven Cascade()
hypernuclei have been experimentally found. Many of these nuclei are of light
masses. We prescribe a new mass formula, called BWMH, which describes the
normal and hypernuclei on the same footing. It is based on the
modified-Bethe-Weizs\"acker mass formula (BWM). BWM is basically an extension
of the Bethe-Weizs\"acker mass formula (BW) for light nuclei. The parameters of
BWM were optimized by fitting about 3000 normal nuclei available recently. The
original Bethe-Weizs\"acker mass formula (BW) was designed for medium and heavy
mass nuclei and it fails for light nuclei. Two earlier works on hypernuclei
based on this BW show some limitations. The BWMH gives improved agreement with
the experimental data for the line of stability, one-neutron separation energy
versus neutron number spectra of normal nuclei, and the hyperon-separation
energies from hypernuclei. The drip lines are modified for addition of a
hyperon in a normal nucleus.Comment: Presented at the "XXIX Mazurian Lakes Conference on Physics: Nuclear
Physics and the Fundamental Processes, Piaski, Poland, August 30 - September
6, 2005." (7 pages, 1 Table, 1 Figure
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