4,079 research outputs found
Test of charge conjugation invariance in the decay of the eta meson into pi(+)pi(-)pi(0)
In this work we present the preliminary results of the analysis of the pp->pp
eta(->pp pi(+)pi(-)pi(0) reaction aiming to test the charge conjugation
symmetry C in strong interactions. Based on approximately identified
eta->pi(+)pi(-)pi(0) decay events we have extracted asymmetry parameters
sensitive to C symmetry violation for different isospin values of the final
state and we have established that all are consistent with zero within the
obtained accuracy.Comment: MESON2012 - 12th International Workshop on Meson Production,
Properties and Interactio
Study of the eta meson production with polarized proton beam
The pp-> pp eta reaction was investigated at excess energies of 15 MeV and 72
MeV using the azimuthally symmetric WASA detector and a polarized proton beam
of the Cooler Synchrotron COSY. The aim of the studies is the determination of
partial wave contributions to the production process of the eta meson in
nucleon-nucleon collisions. Here we present preliminary results of the
extraction of the position of the interaction region with respect to the WASA
detector and preliminary results on the degree of polarization of the COSY
proton beam used in the experiment.Comment: Invited talk at the Second International Symposium on Mesic Nuclei,
Cracow, Poland, September 22-25 201
Magnetic systems at criticality: different signatures of scaling
Different aspects of critical behaviour of magnetic materials are presented
and discussed. The scaling ideas are shown to arise in the context of purely
magnetic properties as well as in that of thermal properties as demonstrated by
magnetocaloric effect or combined scaling of excess entropy and order
parameter. Two non-standard approaches to scaling phenomena are described. The
presented concepts are exemplified by experimental data gathered on four
representatives of molecular magnets.Comment: 33 pages, 16 figure
Pion and Kaon Polarizabilities and Radiative Transitions
CERN COMPASS plans measurements of gamma-pi and gamma-K interactions using
50-280 GeV pion (kaon) beams and a virtual photon target. Pion (kaon)
polarizabilities and radiative transitions will be measured via Primakoff
effect reactions such as pi+gamma->pi'+gamma and pi+gamma->meson. The former
can test a precise prediction of chiral symmetry; the latter for
pi+gamma->a1(1260) is important for understanding the polarizability. The
radiative transition of a pion to a low mass two-pion system, pi+gamma->pi+pi0,
can also be studied to measure the chiral anomaly amplitude F(3pi)
(characterizing gamma->3pi), arising from the effective Chiral Lagrangian. We
review here the motivation for the above physics program. We describe the beam,
target, detector, and trigger requirements for these experiments. We also
describe FNAL SELEX attempts to study related physics via the interaction of
600 GeV pions with target electrons. Data analysis in progress aims to identify
the reactions pi+e->pi'+e'+pi0 related to the chiral anomaly, and
pi+e->pi'+e'+gamma related to pion polarizabilities.Comment: 16 pages, 6 figures, Latex Springer-Verlag style Tel Aviv U. Preprint
TAUP-2469-97, Contribution to the Workshop on Chiral Dynamics Theory and
Experiment, U. of Mainz, Sept. 1-5, 1997, to be published in Springer-Verlag,
Eds. A. Bernstein, Th. Walcher, 199
Preservation of glaciochemical time-series in snow and ice from the Penny Ice Cap, Baffin Island
A detailed investigation of major ion concentrations of snow and ice in the summit region of Penny Ice Cap (PIC) was performed to determine the effects of summer melt on the glaciochemical time-series. While ion migration due to meltwater percolation makes it difficult to confidently count annual layers in the glaciochemical profiles, time-series of these parameters do show good structure and a strong one year spectral component, suggesting that annual to biannual signals are preserved in PIC glaciochemical records
Non-adiabatic scattering of a classical particle in an inhomogeneous magnetic field
We study the violation of the adiabaticity of the electron dynamics in a
slowly varying magnetic field. We formulate and solve exactly a non-adiabatic
scattering problem. In particular, we consider scattering on a magnetic field
inhomogeneity which models scatterers in the composite-fermion theory of the
half-filled Landau level. The calculated non-adiabatic shift of the guiding
center is exponentially small and exhibits an oscillatory behavior related to
the "self-commensurability" of the drifting cyclotron orbit. The analytical
results are complemented with a numerical simulation.Comment: 4 pages REVTEX, 3 figures include
Association between serum heat shock proteins and gamma-delta t cells—an outdated clue or a new direction in searching for an anticancer strategy? A short report
HSPs demonstrate a strong association with gamma-delta (γδ) T cells. Most of the studies regarding interactions between the parameters were conducted in the 1990s. Despite promising results, the concept of targeting γδ T cells by HSPs seems to be a forgotten direction due to potent non-peptidic phosphoantigens rather than HSPs have been found to be the essential stimulatory components for human γδ cells. Currently, with greater knowledge of lymphocyte diversity, and more accurate diagnostic methods, we decided to study the correlation once again in the neoplas-tic condition. Twenty-one children with newly diagnosed acute lymphoblastic leukaemia (ALL) were enrolled on the study. Serum HSP90 concentrations were evaluated by an enzyme-linked immunosorbent assay (ELISA), subsets of γδ T cells (CD3+ γδ, CD3+ γδ HLA/DR+, CD4+ γδ and CD8+ γδ) by flow cytometry. We have shown statistically relevant correlations between serum HSP90 and CD3+ HLA/DR+ γδ T cells in paediatric ALL at diagnosis (R = 0.53, p < 0.05), but not after induction chemotherapy. We also have demonstrated decreased levels of both serum HSP90 and CD3+ HLA/DR+ γδ T cells before treatment, which may indirectly indicate dose-dependent unknown interaction between the parameters. The results of our study may be a good introduction to research on the association between HSPs and CD3+ HLA/DR+ γδ T cells, which could be an interesting direction for the development of anti-cancer strategies, not just for childhood ALL
Determination of the eta'-proton scattering length in free space
Taking advantage of both the high mass resolution of the COSY-11 detector and
the high energy resolution of the low-emittance proton-beam of the Cooler
Synchrotron COSY we determine the excitation function for the pp --> pp eta'
reaction close-to-threshold. Combining these data with previous results we
extract the scattering length for the eta'-proton potential in free space to be
Re(a_{p eta'}) = 0+-0.43 fm and Im(a_{p eta'}) = 0.37(+0.40)(-0.16) fm.Comment: 5 pages, 3 figures, accepted for publication in Phys. Rev. Let
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