11,242 research outputs found
Study of Inclusive Multi-Ring Events from Atmospheric Neutrinos
The current analysis of atmospheric neutrinos by the Super-Kamiokande
Collaboration is based only on fully-contained one-ring events and partially
contained events. We show that the up-down ratio of fully-contained, inclusive,
multi-ring events gives an independent test of the atmospheric neutrino
anomaly, without the need for particle identification. Moreover, this class of
events is rich in neutral current events and hence gives crucial information
for discriminating between oscillations of \nu_\mu into \nu_{e, \tau} and
\nu_s.Comment: 12 pages, 3 figures, LaTeX2e, psfig.st
Deformation of LeBrun's ALE metrics with negative mass
In this article we investigate deformations of a scalar-flat K\"ahler metric
on the total space of complex line bundles over CP^1 constructed by C. LeBrun.
In particular, we find that the metric is included in a one-dimensional family
of such metrics on the four-manifold, where the complex structure in the
deformation is not the standard one.Comment: 20 pages, no figure. V2: added two references, filled a gap in the
proof of Theorem 1.2. V3: corrected a wrong statement about Kuranishi family
of a Hirzebruch surface stated in the last paragraph in the proof of Theorem
1.2, and fixed a relevant error in the proof. Also added a reference [24]
about Kuranishi family of Hirzebruch surface
Right-veering diffeomorphisms of compact surfaces with boundary II
We continue our study of the monoid of right-veering diffeomorphisms on a
compact oriented surface with nonempty boundary, introduced in [HKM2]. We
conduct a detailed study of the case when the surface is a punctured torus; in
particular, we exhibit the difference between the monoid of right-veering
diffeomorphisms and the monoid of products of positive Dehn twists, with the
help of the Rademacher function. We then generalize to the braid group B_n on n
strands by relating the signature and the Maslov index. Finally, we discuss the
symplectic fillability in the pseudo-Anosov case by comparing with the work of
Roberts [Ro1,Ro2].Comment: 25 pages, 5 figure
Nucleosynthesis Modes in the High-Entropy-Wind of Type II Supernovae: Comparison of Calculations with Halo-Star Observations
While the high-entropy wind (HEW) of Type II supernovae remains one of the
more promising sites for the rapid neutron-capture (r-) process, hydrodynamic
simulations have yet to reproduce the astrophysical conditions under which the
latter occurs. We have performed large-scale network calculations within an
extended parameter range of the HEW, seeking to identify or to constrain the
necessary conditions for a full reproduction of all r-process residuals
N_{r,\odot}=N_{\odot}-N_{s,\odot} by comparing the results with recent
astronomical observations. A superposition of weighted entropy trajectories
results in an excellent reproduction of the overall N_{r,\odot}-pattern beyond
Sn. For the lighter elements, from the Fe-group via Sr-Y-Zr to Ag, our HEW
calculations indicate a transition from the need for clearly different sources
(conditions/sites) to a possible co-production with r-process elements,
provided that a range of entropies are contributing. This explains recent
halo-star observations of a clear non-correlation of Zn and Ge and a weak
correlation of Sr - Zr with heavier r-process elements. Moreover, new
observational data on Ru and Pd seem to confirm also a partial correlation with
Sr as well as the main r-process elements (e.g. Eu).Comment: 15 pages, 1 table, 4 figures; To be published in the Astrophysical
Journal Letter
Large-N reduction for N=2 quiver Chern-Simons theories on S^3 and localization in matrix models
We study reduced matrix models obtained by the dimensional reduction of N=2
quiver Chern-Simons theories on S^3 to zero dimension and show that if a
reduced model is expanded around a particular multiple fuzzy sphere background,
it becomes equivalent to the original theory on S^3 in the large-N limit. This
is regarded as a novel large-N reduction on a curved space S^3. We perform the
localization method to the reduced model and compute the free energy and the
vacuum expectation value of a BPS Wilson loop operator. In the large-N limit,
we find an exact agreement between these results and those in the original
theory on S^3.Comment: 46 pages, 11 figures; minor modification
Observation of a Transient Magnetization Plateau in a Quantum Antiferromagnet on the Kagome Lattice
The magnetization process of an S=1/2 antiferromagnet on the kagome lattice,
[Cu_3(titmb)_2(OCOCH_3)_6]H_2O {titmb= 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6
trimethylbenzene} has been measured at very low temperatures in both pulsed and
steady fields. We have found a new dynamical behavior in the magnetization
process: a plateau at one third of the saturation magnetization appears in the
pulsed field experiments for intermediate sweep rates of the magnetic field and
disappears in the steady field experiments. A theoretical analysis using exact
diagonalization yields J_1=-19K and J_2=6K, for the nearest neighbor and second
nearest neighbor interactions, respectively. This set of exchange parameters
explains the very low saturation field and the absence of the plateau in the
thermodynamic equilibrium as well as the two-peak feature in the magnetic heat
capacity. Supported by numerical results we argue that a dynamical order by
disorder phenomenon could explain the transient appearance of the 1/3 plateau
in pulsed field experiments.Comment: 7 pages, 5 figure
Seasoned Psychotherapists\u27 Experience of Difficult Clinical Moments
Purpose: This phenomenological study was concerned with the clarification of the experience of the difficult clinical moment which is defined as a discrete moment in which the psychotherapist experiences distress as a result of his or her work with a client. Method: Retrospective descriptions of experience of difficult clinical moments were obtained from a diverse sample of ten seasoned psychotherapists in the Seattle area. The interviews were transcribed, analyzed, and summarized, and these summaries were confirmed by each participant as being an accurate representation of their experience. Results: Thematic analysis revealed six themes of experience during a difficult clinical moment: 1) Feeling Fear, 2) Feeling Inadequate, 3) Feeling Anger, 4) Feeling Confused, 5) Feeling an Urge to Hide Feelings, and 6) Feeling an Urge to Terminate. An essential general structure of the experience of difficult moments was derived from these themes. Discussion: Conclusions are discussed including: 1) the novel findings of feeling fear and feeling an urge to hide one’s feelings during difficulty; and 2) the urge to hide one’s feelings during difficulty appears to be motivated by both therapist shame and an urge to maintain the therapeutic relationship. Implications are discussed including: 1) the dilemma regarding whether or not a therapist should entertain the urge to hide his or her feelings; and 2) the culture of shame within the field of psychotherapy that stigmatizes therapist difficulties which interferes with consultation. Recommendations for training and research are provided including a recommendation to disseminate these findings to normalize the experience and to encourage therapists and supervisors to discuss difficult clinical moments within consultation, supervision, and training which might reduce the distress of the moment, improve coping skills, provide treatment strategies, and ultimately improve client outcomes. The electronic version of this dissertation is at Ohiolink ETD Center www.ohiolink.ed
Tau Appearance In Atmospheric Neutrino Interactions
If the correct interpretation of the Super-Kamiokande atmospheric neutrino
data is \nu_\mu -> \nu_\tau oscillation, the contained data sample should
already have more than 10 tau appearance events. We study the challenging task
of detecting the tau, focussing on the decay chain \tau^\pm -> \rho^\pm ->
\pi^\pm \pi^0 in events with quasi-elastic tau production. The background
level, which is currently quite uncertain because of a lack of relevant neutral
current data, can be measured by the near detector in the K2K experiment. Our
estimates of the background suggest that it may be possible to detect tau
appearance in Super-Kamiokande with 5-10 years of running.Comment: 13 pages, uses psfi
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