arXiv subjects

M. A. Moinester

Publications and source records attributed to M. A. Moinester.

9 recordsLinked to original sources

arXiv2015

The transverse momentum dependence of charged kaon Bose-Einstein correlations in the SELEX experiment

We report on the measurement of the one-dimensional charged kaon correlation functions using 600~GeV/{\it c} $Σ^-$, $π^-$ and 540~GeV/{\it c} $p$ beams from the SELEX~(E781) experiment at the Fermilab Tevatron. $K^{\pm}K^{\pm}$ correlation functions are studied for three transverse pair momentum, $k_T$, ranges and parameterized by a Gaussian form. The emission source radii, $R$, and the correlation strength, $λ$, are extracted. The analysis shows a decrease of the source radii with increasing kaon transverse pair momentum for all beam types.

hep-ex↗

arXiv2008

Radiative Corrections for Pion Polarizability Experiments

We use the semi-analytical program RCFORGV to evaluate radiative corrections to one-photon radiative emission in the high-energy scattering of pions in the Coulomb field of a nucleus with atomic number Z. It is shown that radiative corrections can simulate a pion polarizability effect. The average effect was estimated for pion energies 40-600 GeV. We also study the range of applicability of the equivalent photon approximation in describing one-photon radiative emission.

hep-ph↗

arXiv2005

Confirmation of the Double Charm Baryon Xi_cc+ via its Decay to p D+ K-

We observes a signal for the double charm baryon Xi_cc+ in the charged decay mode Xi_cc+ -> p D+ K- to complement the previously reported decay Xi_cc+ -> Lambda_c K- pi+ in data from SELEX, the charm hadro-production experiment (E781) at Fermilab. In this new decay mode we observe an excess of 5.62 events over an expected background estimated by event mixing to be 1.38+/-0.13 events. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4E-4. The observed mass of this state is (3518+/-3)MeV/c^2, consistent with the published result. Averaging the two results gives a mass of (3518.7+/-1.7)MeV/c^2. The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio Gamma(Xi_cc+ -> pD+K-)/Gamma(Xi_cc+ -> Lambda_c K- pi+) = 0.36+/-0.21.

hep-ex↗

arXiv2005

A new determination of the $γπ\to ππ$ anomalous amplitude via $π^- e^- \to π^- e^- π^{0}$ data

We discuss the reaction $π^- e^- \to π^- e^- π^{0}$ with the purpose of obtaining information on the $γπ\to ππ$ anomalous amplitude ${\cal F}_{3π}$. We compare a full calculation at ${\cal O}(p^6)$ in chiral perturbation theory and various phenomenological predictions with the existing data of Amendolia {\em et al}. By integrating our theory results using Monte Carlo techniques we obtain $σ= 2.05 $ nb at ${\cal O}(p^6)$ and $σ= 2.17 $ nb after including the dominant electromagnetic correction. Both results are in good agreement with the experimental cross section of $σ= (2.11 \pm 0.47)$ nb. On the basis of the ChPT results one would extract from the the experimental cross section as amplitudes ${\cal F}_{3π}^{(0)\rm extr} = (9.9 \pm 1.1)$ GeV$^{-3}$ and ${\cal F}_{3π}^{(0)\rm extr} = (9.6 \pm 1.1)$ GeV$^{-3}$, respectively, which have to be compared with the low-energy theorem ${\cal F}_{3π}=e/(4π^2 F_π^3)=9.72 {GeV}^{-3}$. We emphasize the need for new data to allow for a comparison of experimental and theoretical distributions and to obtain ${\cal F}_{3π}$ with smaller uncertainty.

hep-ph↗

arXiv2003

Doubly Charmed Baryons in COMPASS

The search for doubly charmed baryons has been a topic for COMPASS from the beginning. Requiring however a complete spectrometer and highest possible trigger rates this measurement has been postponed. The scenario for such a measurement in the second phase of COMPASS is outlined here. First studies of triggering and simulation of the setup have been performed. New rate estimates based on recent measurements from SELEX at FNAL are presented.

hep-ex↗

arXiv2001

Pion Generalized Dipole Polarizabilities by Virtual Compton Scattering $πe \to πeγ$

We present a calculation of the cross section and the event generator of the reaction $πe\to πe γ$. This reaction is sensitive to the pion generalized dipole polarizabilities, namely, the longitudinal electric $α_L(q^2)$, the transverse electric $α_T(q^2)$, and the magnetic $β(q^2)$ which, in the real-photon limit, reduce to the ordinary electric and magnetic polarizabilities $\barα$ and $\barβ$, respectively. The calculation of the cross section is done in the framework of chiral perturbation theory at ${\cal O}(p^4)$. A pion VCS event generator has been written which is ready for implementation in GEANT simulation codes or for independent use.

hep-ph↗

arXiv1998

Kaon Radiative Decay K+ -> mu+ nu gamma at CKM at the Fermilab Main Injector

High statistics data for the K+ -> mu+ nu gamma decay can allow the precision determination of the kaon structure dependent form factors and the kaon polarizability. This study is possible at the proposed FNAL CKM experiment. CKM (Charged Kaons at the Main injector) is a decay-in-flight spectrometer with two RICH, and designed to run at the main injector with a high kaon flux. The radiative decay data will be taken complementary to the primary CKM effort to study the rare kaon decay (K to pi nu nubar) for which CKM was primarily designed. We summarize here the underlying physics of K ->mu nu gamma, the experimental status, and how the CKM spectrometer will be adapted for this study.

hep-ex↗

arXiv1995

How to Search for Pentaquarks in High Energy Hadronic Interactions

The strange-anticharmed Pentaquark is a $uud\bar{c}s$ or $udd\bar{c}s$ five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong and electromagnetic decay. We describe this hyperon here, its structure, binding energy and lifetime, resonance width, production mechanisms, production cross sections, and decay modes. We describe techniques to reduce backgrounds in search experiments and to optimize the conditions for Pentaquark observation. Possibilities for enhancing the signal over background in Pentaquark searches are investigated by examining predictions for detailed momentum and angular distributions in multiparticle final states. General model-independent predictions are presented as well as those from two models: a loosely bound $D_{s}^-N$ molecule and a strongly-bound five-quark system. Fermilab E791 data, currently being analyzed, may have marginal statistics for showing definitive signals. Future experiments in the spirit of the recent CHARM2000 workshop, such as FNAL E781 and CERN CHEOPS with $10^6-10^7$ reconstructed charmed baryon events, should have sensitivity to determine whether or not the Pentaquark exists.

hep-ph↗

arXiv1994

Pentaquark Search with Energetic Hadron Beams

The strange-anticharmed Pentaquark is a uud(cbar)s or udd(cbar)s five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong decay. We describe this hyperon here; its structure, binding energy and lifetime, resonance width, production mechanisms and decay modes. We estimate production cross sections, techniques to reduce backgrounds in search experiments, and how to optimize experiments to observe it. Possibilities for enhancing the signal over background in Pentaquark searches are investigated by examining predictions for detailed momentum and angular distributions in multiparticle final states. General model-independent predictions are presented as well as those from two models: a loosely bound Ds-N "deuteron" and a strongly-bound five-quark model. Fermilab E791 data, currently being analysed, may be marginal for showing definitive signals. Future experiments with more than 10^5 reconstructed charmed baryon events should have sensitivity to determine whether or not the Pentaquark exists.

hep-ph↗