3,141 research outputs found
Observational evidence for a spin-up line in the P-Pdot diagram of millisecond pulsars
It is believed that millisecond pulsars attain their fast spins by accreting
matter and angular momentum from companion stars. Theoretical modelling of the
accretion process suggests a spin-up line in the period-period derivative
(-) diagram of millisecond pulsars, which plays an important role
in population studies of radio millisecond pulsars and accreting neutron stars
in X-ray binaries. Here we present observational evidence for such a spin-up
line using a sample of 143 radio pulsars with < 30 ms. We also find that
PSRs~J18233021A and J18242452A, located near the classic spin-up line,
are consistent with the broad population of millisecond pulsars. Finally, we
show that our approach of Bayesian inference can probe accretion physics,
allowing constraints to be placed on the accretion rate and the
disk-magnetosphere interaction.Comment: 10 pages, 4 figures, 2 tables. Accepted for publication by ApJ
Strong Decays of the Orbitally Excited Scalar Mesons
We calculate the two-body strong decays of the orbitally excited scalar
mesons and by using the relativistic Bethe-Salpeter
(BS) method. was observed recently by the LHCb Collaboration, the
quantum number of which has not been determined yet. In this paper, we assume
that it is the state and obtain the transition amplitude by using the
PCAC relation, low-energy theorem and effective Lagrangian method. For the
state, the total widths of and are 226 MeV
and 246 MeV, respectively. With the assumption of state, the widths
of and are both about 131 MeV, which is close
to the present experimental data. Therefore, is a strong
candidate for the state.Comment: 21 pages, 10 figure
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