3,188 research outputs found
Lunar surface holography experiment instrument feasibility demonstration Final report, 27 Jul. - 30 Nov. 1970
Prototype holocamera and playback system for lunar surface holography experimen
Implications of a DK Molecule at 2.32 GeV
We discuss the implications of a possible quasinuclear DK bound state at 2.32
GeV. Evidence for such a state was recently reported in D_s^+pi^o by the BaBar
Collaboration. We first note that a conventional quark model c-sbar assignment
is implausible, and then consider other options involving multiquark systems.
An I=0 c sbar n nbar baryonium assignment is one possibility. We instead favor
a DK meson molecule assignment, which can account for the mass and quantum
numbers of this state. The higher-mass scalar c-sbar state expected at 2.48 GeV
is predicted to have a very large DK coupling, which would encourage formation
of an I=0 DK molecule. Isospin mixing is expected in hadron molecules, and a
dominantly I=0 DK state with some I=1 admixture could explain both the narrow
total width of the 2.32 GeV state as well as the observed decay to D_s^+ pi^o.
Additional measurements that can be used to test this and related scenarios are
discussed.Comment: 6 pages, 1 figur
Single Atom Detection With Optical Cavities
We present a thorough analysis of single atom detection using optical
cavities. The large set of parameters that influence the signal-to-noise ratio
for cavity detection is considered, with an emphasis on detunings, probe power,
cavity finesse and photon detection schemes. Real device operating restrictions
for single photon counting modules and standard photodiodes are included in our
discussion, with heterodyne detection emerging as the clearly favourable
technique, particularly for detuned detection at high power.Comment: 11 pages, 8 figures, submitted to PRA, minor changes in Secs. I and
IVD.2, and revised Fig.
Legal needs of adults with life-limiting illness: what are they and how are they managed? A qualitative multi-agency stakeholder exercise
Objective: Little is known about legal needs in the context of life-limiting illness, particularly the need for advice concerning legal arrangements, rights and entitlements. This UK-based multiagency stakeholder engagement exercise scoped legal needs associated with life-limiting illness and identified support structures, gaps and opportunities for practice improvement. /
Method and analysis: Snowball sampling generated a stakeholder group from a wide range of regional and national organisations involved in care of people with life-limiting illness, spanning health, social care, legal support, advice, charities, prison services as well as patient and carer representatives. A coproduced survey of three open questions generated qualitative data, interpreted by thematic analysis.
Results Stakeholders reported a broad spectrum of problems and needs raising legal issues, with no consistency of definition. A classification is proposed, identifying matters concerning rights and entitlements of patients/carers in day-to-day life and decisions around care, both immediate and in the future, as well as professional responsibilities in delivering personalised care. The support structures identified were predominantly online literature, although there was some availability of remote and face-to-face services. Limited awareness of the issues, variable service configuration, fragmentation of care and inequitable access were identified as barriers to support. Stakeholders recognised the need for education and closer multiagency working. /
Conclusions: ‘Legal needs’ incorporate wide-ranging issues, but there is inconsistency in perceptions among stakeholders. Practice is variable, risking unmet need. Opportunities for improvement include more formal integration of social welfare legal services in the health context, generating clearer pathways for assessment and management
A chromomagnetic mechanism for the X(3872) resonance
The chromomagnetic interaction, with proper account for flavour-symmetry
breaking, is shown to explain the mass and coupling properties of the X(3872)
resonance as a = 1 state consisting of a heavy quark-antiquark
pair and a light one. It is crucial to introduce all the spin-colour
configurations compatible with these quantum numbers and diagonalise the
chromomagnetic interaction in this basis. This approach thus differs from the
molecular picture and from the diquark-antidiquark picture.Comment: 4 pages - revtex4 - Typos corrected, refs. added, to be published in
Phys. Rev.
A detector for continuous measurement of ultra-cold atoms in real time
We present the first detector capable of recording high-bandwidth real time
atom number density measurements of a Bose Einstein condensate. Based on a
two-color Mach-Zehnder interferometer, our detector has a response time that is
six orders of magnitude faster than current detectors based on CCD cameras
while still operating at the shot-noise limit. With this minimally destructive
system it may be possible to implement feedback to stabilize a Bose-Einstein
condensate or an atom laser.Comment: 3 pages, 3 figures, submitted to optics letter
Decisive Search for a Diquark-Antidiquark Meson with Hidden Strangeness
Diquark-antidiquark states are expected to exist as a natural complement of
mesons and baryons. Although they were predicted long ago, and some candidates
were found experimentally, none has, as yet, been reliably identified. We
suggest that the search for the so-called -meson in reactions such as
photoproduction and should provide a decisive way to settle this issue. Estimates of the
cross sections are given using present experimental information on the C-meson
and assuming its diquark-antidiquark structure. Sizable cross sections are
predicted (of the order of 0.1 b for photoproduction and of the order of
0.1 mb for at the maximum with an insignificant background). Failure to
find this kind of signal would imply that the C-meson is {\it not} a
diquark-antidiquark state.Comment: 9 pages in LATex + 6 figs. (available from authers upon request),
IUHET-269/9
Universality of Leading Relativistic Corrections to Bound State Gyromagnetic Ratios
We discuss the leading relativistic (nonrecoil and recoil) corrections to
bound state -factors of particles with arbitrary spin. These corrections are
universal for any spin and depend only on the free particle gyromagnetic
ratios. We explain the physical reasons behind this universality.Comment: 10 pp., based on talks given at the Gribov-80 Memorial Workshop,
ICTP, Trieste, Italy, May 2010 and at PSAS 2010 workshop, Les Houches, June
2010. To be published in the Gribov-80 Proceedings and in Can. J. Phy
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