1,478 research outputs found
In-Medium Modifications of Low-Mass Vector Mesons in PHENIX at RHIC
Measurements at RHIC have established the creation of a Quark Gluon Plasma
(QGP) in most central heavy-ion collisions. An important tool to understand
properties of the QGP is study of the spectral shapes of low-mass vector mesons
(LVM's), , and , which can be modified in the medium by
partial restoration of chiral symmetry. This modification may be accessed
directly by measuring low-momentum LVM's via their decays into lepton pairs
inside the hot matter. Since leptons are not subject to the strong interaction,
they do not rescatter on their way out of the medium. The PHENIX experiment at
RHIC has measured LVM production at mid-rapidity in + , +Au and Au+Au
collisions at = 200 GeV\@. Mass peaks for the LVM's have
been observed in the di-electron invariant mass spectra with a resolution of 10
MeV/ in all of the three collision systems. The extracted spectra, mass
and width of and in + , +Au and Au+Au, in the
leptonic and hadronic decay channels are reviewed. As the widths of the mesons
may be affected in the medium, the branching ratios of various decay modes may
also be modified from the values in vacuum. The relative branching ratio is
compared between and , which may be sensitive
to the mass modification due to the small Q-value of .Comment: 4 pages, 4 figure
The group of automorphisms of the first weyl algebra in prime characteristic and the restriction map
Let K be a perfect field of characteristic p > 0; A(1) := K be the first Weyl algebra; and Z := K[X := x(p), Y := partial derivative(p)] be its centre. It is proved that (1) the restriction map res : Aut(K)(A(1)) -> Aut(K)(Z), sigma bar right arrow sigma vertical bar(Z) is a monomorphism with im(res) = Gamma := (tau is an element of Aut(K)(Z) vertical bar J(tau) = 1), where J(tau) is the Jacobian of tau, (Note that Aut(K)(Z) = K* (sic) Gamma, and if K is not perfect then im(res) not equal Gamma.); (ii) the bijection res : Aut(K)(A(1)) -> Gamma is a monomorphism of infinite dimensional algebraic groups which is not an isomorphism (even if K is algebraically closed); (iii) an explicit formula for res(-1) is found via differential operators D(Z) on Z and negative powers of the Fronenius map F. Proofs are based on the following (non-obvious) equality proved in the paper: (d/dx + f)(p) = (d/dx)(p) + d(p-1)f/dx(p-1) + f(p), f is an element of K[x]
Arrival time distributions of electrons in air showers with primary energies above 10 (18)eV observed at 900m above sea level
Detection of air showers with primary energies above 10 to the 19th power eV with sufficient statistics is extremely important in an astrophysical aspect related to the Greisen cut off and the origin of such high energy cosmic rays. Recently, a method is proposed to observe such giant air showers by measuring the arrival time distributions of air-shower particles at large core distances with a mini array. Experiments to measure the arrival time distributions of muons were started in 1981 and those of electrons in early 1983 in the Akeno air-shower array (930 gcm cm squared atmospheric depth, 900m above sea level). During the time of observation, the detection area of the Akeno array was expanded from 1 sq km to sq km in 1982 and to 20 sq km in 1984. Now the arrival time distribution of electrons and muons can be measured for showers with primary energies above 1019eV at large core distances
Quantum interface between photonic and superconducting qubits
We show that optically active coupled quantum dots embedded in a
superconducting microwave cavity can be used to realize a fast quantum
interface between photonic and transmon qubits. Single photon absorption by a
coupled quantum dot results in generation of a large electric dipole, which in
turn ensures efficient coupling to the microwave cavity. Using cavity
parameters achieved in prior experiments, we estimate that bi-directional
microwave-optics conversion in nanosecond timescales with efficiencies
approaching unity is experimentally feasible with current technology. We also
outline a protocol for in-principle deterministic quantum state transfer from a
time-bin photonic qubit to a transmon qubit. Recent advances in quantum dot
based quantum photonics technologies indicate that the scheme we propose could
play a central role in connecting quantum nodes incorporating cavity-coupled
superconducting qubits
Longitudinal development of muons in large air showers studies from the arrival time distributions measured at 900m above sea level
The arrival time distributions of muons with energies above 1.0GeV and 0.5GeV have been measured in the Akeno air-shower array to study the longitudinal development of muons in air showers with primary energies in the range 10 to the 17th power to 10 to the 18th power ev. The average rise times of muons with energies above 1.0GeV at large core distances are consistent with those expected from very high multiplicity models and, on the contrary, with those expected from the low multiplicity models at small core distances. This implies that the longitudinal development at atmospheric depth smaller than 500 cm square is very fast and that at larger atmospheric depths is rather slow
On the eigenvector algebra of the product of elements with commutator one in the first Weyl algebra
Let be the (first) Weyl algebra over a field of
characteristic zero. It is known that the set of eigenvalues of the inner
derivation \ad (YX) of is . Let A_1\ra A_1, ,
, be a -algebra homomorphism, i.e. . It is proved that
the set of eigenvalues of the inner derivation \ad (yx) of the Weyl algebra
is and the eigenvector algebra of \ad (yx) is (this
would be an easy corollary of the Problem/Conjecture of Dixmier of 1968 [still
open]: {\em is an algebra endomorphism of an automorphism?}).Comment: 16 page
Evaluation of contour of unruptured cerebral aneurysm using three-dimensional CT cisternogram.
Angiography is gold standard technique as preoperative examination for unruptured aneurysmal surgery. Neurosurgeons have observed the unexpected irregular shape and size of the aneurysmal dome and neck in many cases of unruptured cerebral aneurysms during aneurysmal microsurgery, and known the discrepancy between the findings of angiography and operative view. We could not find out the report described the preoperative evaluation of outer-wall (contour) of aneurysm. In the present study, we attempted to evaluate the outer-wall of an unruptured cerebral aneurysm using three-dimensional CT cisternogram (3D-CTC) to provide useful preoperative information. The study was performed on three cases of unruptured cerebral aneurysm that were identified incidentally by MR angiography. We performed three-dimensional CT aniography (3D-CTA) and 3D-CTC for each patient. In the present study, we visualized the contours of vessels and aneurysms using a 3D-CTC in three cases of unruptured cerebral aneurysm. We found the discrepancy between the 3D-CTC contour image and the intra-luminal image 3D-CTA image. This method may be useful for the decision of the surgical approach and have the potential to evaluate the anatomical structure of aneurysmal dome and neck preoperatively.</p
Lansoprazole Novel Effector Sites Revealed by Autoradiography: Relation to Helicobacter pylori, Colon, Esophagus and Others
Lansoprazole uptake sites by two kinds of autoradiographic procedures were compared with recent literature. The uptake sites have been seen in the Helicobacter pylori, colonic epithelial cells, inflammatory cells, peripheral autonomic nerves and enterochromaffinlike cells as well as gastric parietal cells. Each uptake sites corresponded to the reported localization of P-type ATPase or acidic compartment
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