Suppression of Non-photonic Electrons from Enhancement of Charm Baryons in Heavy Ion Collisions

At intermediate transverse momentum (2 < p_T < 6 GeV/c), baryon production in Au+Au collisions is enhanced compared to p+p collisions. Since charm baryon decays produce electrons less frequently than charm meson decays, the non-photonic electron spectrum is sensitive to the Lambda_c/D ratio. In this report we study the dependence of the non-photonic electron spectrum on the baryon-to-meson ratio for charm hadrons. As an example, we take the Lambda_c/D ratio to have the same form as the Lambda/K^0_S ratio. In this case, even if the total charm quark yield in Au+Au collisions scales with the number of binary nucleon-nucleon collisions (N_bin), the electron spectrum at 2 < p_T < 5 GeV/c is suppressed relative to N_bin scaled p+p collisions by as much as 20%.Comment: Added STAR data to figure 1 and made slight text modifications (fixed figure replacement

Study of hyperfine structure in simple atoms and precision tests of the bound state QED

We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.Comment: presented at The International Workshop "e+e- collisions from phi to psi

Nostos - Spherical TPCs

A new concept, the spherical TPC, presents unique advantages when low energy neutrinos are to be detected. Some of the applications are: a) observation of the e oscillation when emitted by a tritium source ( = 14 keV) in a 10 m radius sphere. This project, baptized NOSTOS, intends to give the mixing angle 13, the Weinberg angle and a much lower limit (< 10-12 ?B) of the neutrino magnetic moment, b) an array of small (radius 2-4 m), cheap spheres scattered around the world would be perfect to monitor extragalactic supernovae, c) detect the spectrum of low energy (pp - 7Be) solar neutrinos.Comment: XIII International Symposium on Very High Energy Cosmic Ray Interactions at the NESTOR Institute - Pylos, Grece, 6-12 Septembre 200

Final State Interactions in Decays of the Exotic π1\pi_{1} Meson

We analyze the role of final state interactions in decay of the lighest exotic meson, $pi_1$ with $J^{PC}=1^{-+}. We use the relativistic Lippmann-Schwinger equation for two coupled$\pi b_{1}$and$\pi\rho$channels. The first one is the predicted dominant decay mode of the$\pi_{1}$, whereas in the other a narrow$\pi_1(1600)$exotic signal has been reported by the E852 collaboration. The FSI potential is constructed, based on the$\omega$meson exchange between the two channels. We find that this process introduces corrections to the$\pi_{1}$widths of the order of only a few MeV. Therefore, we conclude that a substantial$\pi\rho$ mode cannot be generated through level mixing.Comment: 7 pages, 11 figure

MesonNet Workshop on Meson Transition Form Factors

The mini-proceedings of the Workshop on Meson Transition Form Factors held in Cracow from May 29th to 30th, 2012 introduce the meson transition form factor project with special emphasis on the interrelations between the various form factors (on-shell, single off-shell, double off-shell). Short summaries of the talks presented at the workshop follow.Comment: 69 pages, 14 figures; all talks can be found at https://sites.google.com/site/mesonnetwork/home/activities/form-factor-workshop-2012; v2: workshop link updated (as the page had to be moved to a commercial server), table 6 correcte

Implicit QR for Companion-like Pencils

A fast implicit QR algorithm for eigenvalue computation of low rank corrections of unitary matrices is adjusted to work with matrix pencils arising from polynomial zerofinding problems . The modified QZ algorithm computes the generalized eigenvalues of certain NxN rank structured matrix pencils using O(N^2) ops and O(N) memory storage. Numerical experiments and comparisons confirm the effectiveness and the stability of the proposed method

Survival before annihilation in Psi-prime decays

We extend the simple scenario for $\Psi'$ decays suggested a few years ago. The $c\bar c$ pair in the $\Psi'$ does not annihilate directly into three gluons but rather survives before annihilating. An interesting prediction is that a large fraction of all $\Psi'$ decays could originate from the $\Psi' \to \eta_{c} (3\pi)$ channel which we urge experimentalists to identify. Our model solves the problem of the apparent hadronic excess in $\Psi'$ decays as well as the $\rho\pi$ puzzle since, in our view, the two-body decays of the $\Psi'$ are naturally of electromagnetic origin. Further tests of this picture are proposed, e.g. $J/\Psi \to b_{1}\eta$.Comment: 6 pages, no figur