arXiv subjects

Igor Strakovsky

Publications and source records attributed to Igor Strakovsky.

30 records · Page 2Linked to original sources

arXiv2021

Strange Hadron Spectroscopy with Secondary KL Beam in Hall D

We propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with the GlueX experimental setup for strange hadron spectroscopy. The superior CEBAF electron beam will enable a flux on the order of $1\times 10^4~K_L/sec$, which exceeds the flux of that previously attained at SLAC by three orders of magnitude. The use of a deuteron target will provide first measurements ever with neutral kaons on neutrons. The experiment will measure both differential cross sections and self-analyzed polarizations of the produced $Λ$, $Σ$, $Ξ$, and $Ω$ hyperons using the GlueX detector at the Jefferson Lab Hall D. The measurements will span CM $\cosθ$ from $-0.95$ to 0.95 in the range W = 1490 MeV to 2500 MeV. The new data will significantly constrain the partial wave analyses and reduce model-dependent uncertainties in the extraction of the properties and pole positions of the strange hyperon resonances, and establish the orbitally excited multiplets in the spectra of the $Ξ$ and $Ω$ hyperons. Comparison with the corresponding multiplets in the spectra of the charm and bottom hyperons will provide insight into he accuracy of QCD-based calculations over a large range of masses. The proposed facility will have a defining impact in the strange meson sector through measurements of the final state $Kπ$ system up to 2 GeV invariant mass. This will allow the determination of pole positions and widths of all relevant $K^\ast(Kπ)$ $S$-,$P$-,$D$-,$F$-, and $G$-wave resonances, settle the question of the existence or nonexistence of scalar meson $κ/K_0^\ast(700)$ and improve the constrains on their pole parameters. Subsequently improving our knowledge of the low-lying scalar nonet in general.

nucl-ex↗

arXiv2020

Precision measurements of A=3 nuclei in Hall B

We propose a high-statistics measurement of few body nuclear structure and short range correlations in quasi-elastic scattering at 6.6 GeV from $^2$H, $^3$He and $^3$H targets in Hall B with the CLAS12 detector. We will measure absolute cross sections for $(e,e'p)$ and $(e,e'pN)$ quasi-elastic reaction channels up to a missing momentum $p_{miss} \approx 1$ GeV/c over a wide range of $Q^2$ and $x_B$ and construct the isoscalar sum of $^3$H and $^3$He. We will compare $(e,e'p)$ cross sections to nuclear theory predictions using a wide variety of techniques and $NN$ interactions in order to constrain the $NN$ interaction at short distances. We will measure $(e,e'pN)$ quasi-elastic reaction cross sections and $(e,e'pN)/(e,e'p)$ ratios to understand short range correlated (SRC) $NN$ pairs in the simplest non-trivial system. $^3$H and $^3$He, being mirror nuclei, exploit the maximum available isospin asymmetry. They are light enough that their ground states are readily calculable, but they already exhibit complex nuclear behavior, including $NN$ SRCs. We will also measure $^2$H$(e,e'p)$ in order to help theorists constrain non-quasielastic reaction mechanisms in order to better calculate reactions on $A=3$ nuclei. Measuring all three few body nuclei together is critical, in order to understand and minimize different reaction effects, such as single charge exchange final state interactions, in order to test ground-state nuclear models. We will also measure the ratio of inclusive $(e,e')$ quasi-elastic cross sections (integrated over $x_B$) from $^3$He and $^3$H in order to extract the neutron magnetic form factor $G_M^n$ at small and moderate values of $Q^2$. We will measure this at both 6.6 GeV and 2.2 GeV.

nucl-ex↗

arXiv2020

Deciphering the mechanism of near-threshold $J/ψ$ photoproduction

The photoproduction of the $J/ψ$ off the proton is believed to deepen our understanding of various physics issues. On the one hand, it is proposed to provide access to the origin of the proton mass, based on the QCD multipole expansion. On the other hand, it can be employed in a study of pentaquark states. The process is usually assumed to proceed through vector-meson dominance, that is the photon couples to a $J/ψ$ which rescatters with the proton to give the $J/ψp$ final state. In this Letter, we provide a compelling hint for and propose measurements necessary to confirm a novel production mechanism via the $Λ_c \bar D^{(*)}$ intermediate states. In particular, there must be cusp structures at the $Λ_c \bar D^{(*)}$ thresholds in the energy dependence of the $J/ψ$ photoproduction cross section. The same mechanism also implies the $J/ψ$-nucleon scattering lengths of order 1 mfm. Given this, one expects only a minor contribution of charm quarks to the nucleon mass.

hep-ph↗

arXiv2020

Conceptual Design of Beryllium Target for the KLF Project

The Kaon Production Target (KPT) is an important component of the proposed K-Long facility which will be operated in JLab Hall~D, targeting strange baryon and meson spectroscopy. In this note we present a conceptual design for the Be-target assembly for the planned K-Long beam line, which will be used along with the GlueX spectrometer in its standard configuration for the proposed experiments. The high quality 12-GeV CEBAF electron beam enables production of a K$_L$ flux at the GlueX target on the order of $1\times 10^4 K_L/sec$, which exceeds the K$_L$ flux previously attained at SLAC by three orders of magnitude. An intense K$_L$ beam would open a new window of opportunity not only to locate "missing resonances" in the strange hadron spectrum, but also to establish their properties by studying different decay channels systematically. The most important and radiation damaging background in K$_L$ production is due to neutrons. The Monte Carlo simulations for the proposed conceptual design of KPT show that the resulting neutron and gamma flux lead to a prompt radiation dose rate for the KLF experiment that is below the JLab Radiation Control Department radiation dose rate limits in the experimental hall and at the site boundary, and will not substantially affect the performance of the spectrometer.

physics.ins-det↗

arXiv2020

Comparative analysis of $ωp$, $ϕp$, and $J/ψp$ scattering lengths from A2, CLAS, and GlueX threshold measurements

The high accuracy $ϕ$-meson photoproduction data from the CLAS experiment in Hall~B of Jefferson Laboratory allow us to determine the near-threshold total cross section of the $γp\toϕp$ reaction and use it for evaluating the $ϕp$ scattering length $α_{ϕp}$. These data result in an absolute value of $|α_{ϕp}| = (0.063\pm 0.010)$~fm, which is smaller than the typical hadron size. A comparative analysis of $α_{ϕp}$ with the previously determined scattering lengths for $ωp$ and $J/ψp$ from the A2 and GlueX experiments is performed.

hep-ph↗

arXiv2019

J/$ψ$p Scattering Length from GlueX Threshold Measurements

The quality of the recent GlueX $J/ψ$ photoproduction data from Hall~D at Jefferson Laboratory, and the proximity of the data to the energy threshold, gives access to a variety of interesting physics aspects. As an example, an estimation of the $J/ψ$-nucleon scattering length $α_{J/ψp}$ is provided within the vector meson dominance model. It results in $|α_{J/ψp}| = (3.08\pm 0.55 ({\rm stat.}) \pm 0.45 ({\rm syst.}))$~mfm.

hep-ph↗

arXiv2019

Photoproduction Reactions and Non-Strange Baryon Spectroscopy

We review the last two decades of using photon beams to measure the production of mesons, and in particular the information that can be obtained on the spectrum of light, non-strange baryons. This is a compendium of experimental results, which should be used as a complement to theoretical reviews of the subject. Lists of data sets are given, together with a comprehensive set of references. An indication of the impact of the data is presented with a summary of the results.

nucl-ex↗

arXiv2015

Helicity Asymmetry Measurement for $π^0$ Photoproduction on the CLAS Frozen Spin Target

The measurement was performed with circularly polarized photons incident on longitudinally polarized target in Hall B at the Thomas Jefferson National Accelerator Facility. The helicity asymmetry E for $\vecγ\vec{p}\toπ^0p$ was determined at CM energies between 1450 MeV and 2050 MeV and compared to the SAID, MAID, and BnGa partial-wave analyses.

nucl-ex↗

arXiv2015

Progress in Neutron EM Couplings

An overview of the GW SAID and ITEP groups' effort to analyze pion photoproduction on the neutron-target will be given. The disentanglement of the isoscalar and isovector EM couplings of N* and Delta* resonances does require compatible data on both proton and neutron targets. The final-state interaction plays a critical role in the state-of-the-art analysis in extraction of the gn-->piN data from the deuteron target experiments. Then resonance couplings determined by the SAID PWA technique are then compared to previous findings. The neutron program is important component of the current JLab, MAMI-C, SPring-8, ELSA, and ELPH studies.

nucl-th↗

arXiv2014

Exotics and PWA for piN Scattering

Our talk is intended for the session in memory of Mitya Diakonov. The problem is considered of existence of flavor multiplets consisting of multi-quark baryons. We have argued that the S-matrix should have poles, at least Regge ones, with any quantum numbers, including exotic. This is a novel argument for possible a proof, yet there are no theoretical arguments to forbid exotics. Then we apply the partial-wave analysis (PWA) with addressing mainly to the non-strange exotic members of the anti-decuplet or even of higher multiplets. It suggested new N(1680) as a possible partner of Theta+. Later independent measurements of several collaborations seem to support our finding for N(1680), though its quantum numbers still wait for investigation. Similar approach to pi+ - proton scattering, in combination with K+ - proton scattering, suggests a number of candidates for 27-plets. Their interesting feature is possible existence of both very wide and very narrow baryon states. This phenomenon may be analogous to recent Weinberg's suggestion for tetra-quark mesons. The situation is worth of further theoretical and experimental studies.

hep-ph↗

arXiv2014

SAID Analysis of Meson Photoproduction : Determination of Neutron and Proton EM Couplings

We present an overview of the GW SAID group effort to analyze on new pion photoproduction on both proton- and neutron-targets. The main database contribution came from the recent CLAS and MAMI unpolarized and polarized measurements. The differential cross section for the processes gamma n --> pi- p was extracted from new measurements accounting for Fermi motion effects in the impulse approximation (IA) as well as NN and piN effects beyond the IA. The EM coupling results are compared to other recent studies.

hep-ph↗

arXiv1997

Analysis of the pp-->pp, pid-->pid, and pid-->pp Scattering Data

A combined analysis of the main reactions of the two-baryon system (pp-->pp, pid-->pid, and pid-->pp) over the sqrt{s} interval from pion threshold to 2.4 GeV has been completed. The overall phase in pid-->pp has now been determined. The combined analysis has resulted in an improved fit to the pid elastic and pid-->pp databases.

nucl-th↗