9,204 research outputs found
Towards an Understanding of the New Charm and Charm-Strange Mesons
The observation of the D_{sJ}^*(2317), D_{sJ}(2460), and SELEX D^*_{sJ}(2632)
states with properties differing considerably from what was expected has led to
a renewed interest in hadron spectroscopy. In addition to these states,
non-strange partners of the D_{sJ} states have also been observed.
Understanding the D_0^* and D_1' states can provide important insights into the
D_{sJ} states. In this contribution I examine quark model predictions for the
D_0^* and D_1' states and discuss experimental measurements that can shed light
on them. I find that these states are well described as the broad, j=1/2
non-strange charmed P-wave mesons. In the latter part of this writeup I discuss
the c bar{s} possibilities for the SELEX D^*_{sJ}(2632) and measurements that
can shed light on it.Comment: Talk presented at the 1st Meeting of the APS Topical Group on
Hadronic Physics (Fermilab, Oct 24-26, 2004). 4 pages uses jpcon
Discovery Potential for New Phenomena
We examine the ability of future facilities to discover and interpret
non-supersymmetric new phenomena. We first explore explicit manifestations of
new physics, including extended gauge sectors, leptoquarks, exotic fermions,
and technicolor models. We then take a more general approach where new physics
only reveals itself through the existence of effective interactions at lower
energy scales. [Summary Report of the New Phenomena Working Group. To appear in
the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High
Energy Physics - Snowmass96, Snowmass, CO, 25 June - 12 July 1996.]Comment: 18 pages, LaTex2
On the population of remnant FRII radio galaxies and implications for radio source dynamics
The purpose of this work is two-fold: (1) to quantify the occurrence of
ultra-steep spectrum remnant FRII radio galaxies in a 74 MHz flux limited
sample, and (2) perform Monte-Carlo simulations of the population of active and
remnant FRII radio galaxies to confront models of remnant lobe evolution, and
provide guidance for further investigation of remnant radio galaxies. We find
that fewer than 2 of FRII radio galaxies with S Jy are
candidate ultra-steep spectrum remnants, where we define ultra-steep spectrum
as . Our Monte-Carlo simulations
demonstrate that models involving Sedov-like expansion in the remnant phase,
resulting in rapid adiabatic energy losses, are consistent with this upper
limit, and predict the existence of nearly twice as many remnants with normal
(not ultra-steep) spectra in the observed frequency range as there are
ultra-steep spectrum remnants. This model also predicts an ultra-steep remnant
fraction approaching 10 at redshifts . Importantly, this model
implies the lobes remain over-pressured with respect to the ambient medium well
after their active lifetime, in contrast with existing observational evidence
that many FRII radio galaxy lobes reach pressure equilibrium with the external
medium whilst still in the active phase. The predicted age distribution of
remnants is a steeply decreasing function of age. In other words young remnants
are expected to be much more common than old remnants in flux limited samples.
For this reason, incorporating higher frequency data GHz will be of
great benefit to future studies of the remnant population.Comment: 19 pages, 8 figures, 4 table
Dynamics and Decay of Heavy-Light Hadrons
Recent signals for narrow hadrons containing heavy and light flavours are
compared with quark model predictions for spectroscopy, strong decays, and
radiative transitions. In particular, the production and identification of
excited charmed and cs states are examined with emphasis on elucidating the
nature of and states. Roughly 200 strong decay amplitudes of
and states up to 3.3 GeV are presented. Applications include determining
flavour content in mesons and the mixing angle in and wave
states and probes of putative molecular states. We advocate searching for
radially excited states in B decays.Comment: 19 pages, 7 figures, revtex. A numerical error is corrected. Some
strong decay rates have change
Properties of the Charmed P-wave Mesons
Two broad charmed mesons, the D_0^* and D_1', have recently been observed. We
examine the quark model predictions for the D_0^* and D_1' properties and
discuss experimental measurements that can shed light on them. We find that
these states are well described as the broad, j=1/2 non-strange charmed P-wave
mesons. Understanding the D_0^* and D_1' states can provide important insights
into the D_{sJ}^*(2317), D_{sJ}(2460) states whose unexpected properties have
led to renewed interest in hadron spectroscopy.Comment: 7 pages. Some additional discussion and reference
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