4,128 research outputs found
Production of , , and in hadronic decays
A coherent study of the production of (, 2, 3 corresponding to
, , and ) in is
reported based on a previously proposed glueball and nonet mixing
scheme, and a factorization for the decay of , where
denotes the isoscalar vector mesons and , and denotes
pseudoscalar mesons. The results show that the decays are very
sensitive to the structure of those scalar mesons, and suggest a glueball in
the GeV region, in line with Lattice QCD. The presence of significant
glueball mixings in the scalar wavefunctions produces peculiar patterns in the
branching ratios for , which are in good agreement
with the recently published experimental data from the BES collaboration.Comment: Version accepted by PRD; Numerical results in Tab IV and VI changed
due to correction of an error in quoting an experimental datum; Conclusion is
not change
The role of secondary Reggeons in central meson production
We estimate the contribution of f_2 trajectory exchange to the central \eta
and \eta^\prime production. It is shown that secondary Reggeons may give a
large contribution to processes of double diffractive meson production at high
energy.Comment: 7 pages, Latex, 5 figure
Glueball enhancements in p(gamma,VV)p through vector meson dominance
Double vector meson photoproduction, p(gamma, G -> VV)p, mediated by a scalar
glueball G is investigated. Using vector meson dominance (VMD) and
Regge/pomeron phenomenology, a measureable glueball enhancement is predicted in
the invariant VV = rho rho and omega omega mass spectra. The scalar glueball is
assumed to be the lightest physical state on the daughter pomeron trajectory
governing diffractive vector meson photoproduction. In addition to cross
sections, calculations for hadronic and electromagnetic glueball decays, G -> V
V' (V,V'= rho, omega, phi, gamma), and gamma_v V -> G transition form factors
are presented based upon flavor universality, VMD and phenomenological
couplings from phi photoproduction analyses. The predicted glueball decay
widths are similar to an independent theoretical study. A novel signature for
glueball detection is also discussed
Nuclear Shadowing in the Structure Function
Nuclear modification of the structure function is investigated.
Although it could be estimated in the medium and large regions from the
nuclear structure function , it is essentially unknown at small . The
nuclear structure function at small is investigated in two
different theoretical models: a parton-recombination model with rescaling
and an aligned-jet model. We find that these models predict completely
different behavior at small : {\it antishadowing} in the first parton model
and {\it shadowing} in the aligned-jet model. Therefore, studies of the ratio
at small could be useful in discriminating among different
models, which produce similar shadowing behavior in the structure function
. We also estimate currently acceptable nuclear modification of at
small by using experimental data and baryon-number
conservation.Comment: 10 pages, Latex, Figs.1 and 2 are not included, Complete postscript
file including the figures is available at
ftp://ftp.cc.saga-u.ac.jp/pub/paper/riko/quantum1/saga-he-78.ps.gz or at
http://www.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.htm
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
Evaluation of valued youth: a national peer-tutoring programme to increase self confidence and motivation
Established first in the USA, Valued Youth has operated in the UK since 1996, and is currently implemented in about 50 schools in 8 regions. The programme is intended to help secondary school students who are at risk of disengaging with school or underperforming for a variety of reasons. These students are selected as tutors, given training on how to work with younger children and placed in a local primary school where they support pupils' learning. Valued Youth can be seen as one of many initiatives in secondary schools on re-engagement in learning and contributes to the UK government strategy of extending opportunities and providing flexible learning experiences to meet individual learners' needs and aptitudes.
Evidence from the USA has shown the value of the programme in reducing drop-out, strengthening youngsters' perceptions of self and school, and reducing disciplinary referrals and absenteeism. The evaluation discussed in this paper considers the effect of the programme in a UK context, not only in terms of young people's attendance, attainment and confidence, but also in terms of what sort of youngsters seem to benefit and the effects of financial rewards, if any, on the outcomes.
The paper reports on the first year of a two-year evaluation. Data were obtained from a pre- and post-questionnaire survey among tutors, a workshop with coordinators and visits to selected case study schools in several regions. Almost all tutors enjoyed the programme and would recommend the experience to others. There was a relatively low dropout and the programme was warmly appreciated by participating primary schools. We have evidence that Valued Youth markedly raises confidence, improves communication skills and keeps some at risk youngsters on track in school. Many types of youngsters benefit from the experience; those who lack confidence and have poor communication skills seem to make the most progress. Successful tutors tend to be those who are committed to the programme, willing to learn, are flexible and cooperative, and have some ability to interact with others, particularly children and primary teachers.</p
Diagnostic Decays of the X(3872)
The unusual properties of the X(3872) have led to speculation that it is a
weakly bound state of mesons, chiefly . Tests of this
hypothesis are investigated and it is proposed that measuring the , , , , and decay
modes of the will serve as a definitive diagnostic of the molecule
hypothesis.Comment: 6 pages revtex4, 3 eps figure
Radiative decays: a new flavour filter
Radiative decays of the orbital excitations of the ,
and to the scalars , and are shown to
provide a flavour filter, clarifying the extent of glueball mixing in the
scalar states. A complementary approach to the latter is provided by the
radiative decays of the scalar mesons to the ground-state vectors ,
and . Discrimination among different mixing scenarios is strong.Comment: 12 pages, 1 table, 0 figure
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