Balewski, J.T
[2.0, 5.0]
Max results
Sort by Reverse order

Showing 10 of 70 results

Differential cross sections for backward π− p → nπ0 from 2.6 to 8 GeV/c

DeMarzo, C. ; Guerriero, L. ; Nicolini, C. ; et al.
Phys.Lett.B 56 (1975) 487-490, 1975.
Inspire Record 1389073 DOI 10.17182/hepdata.27860

We report differential cross sections for π − p → n π 0 in the backward hemisphere at incident momenta of 2.6, 3.5, 4.3, 6.0, and 8.0 GeV/c. We observe less pronounced structure than some previous measurements with a shallow dip displaced from that seen in π + p elastic scattering.

5 data tables
More…

Precision measurements of $g_1$ of the proton and the deuteron with 6 GeV electrons

The CLAS collaboration Prok, Y. ; Bosted, P. ; Kvaltine, N. ; et al.
Phys.Rev.C 90 (2014) 025212, 2014.
Inspire Record 1292133 DOI 10.17182/hepdata.64411

The inclusive polarized structure functions of the proton and deuteron, g1p and g1d, were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at lab angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual DIS kinematics, Q^2>1 GeV^2 and the final-state invariant mass W>2 GeV, the ratio of polarized to unpolarized structure functions g1/F1 is found to be nearly independent of Q^2 at fixed x. Significant resonant structure is apparent at values of W up to 2.3 GeV. In the framework of perturbative QCD, the high-W results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions.

4 data tables
Table 1

Results for G1(P)/F1(P) for the proton in bins of (XB;Q**2), along with average kinematic values and correction factors for each bin. All values are averaged over the event distribution.

Table 2

Results for G1(DEUT)/F1(DEUT) for the deuteron in bins of (XB;Q**2), along with average kinematic values and correction factors for each bin. All values are averaged over the event distribution.

Table 3

Results for G1(P)/F1(P) for the proton in bins of (W;Q**2), along with average kinematic values and correction factors for each bin. All values are averaged over the event distribution.

More…

Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab

The CLAS collaboration McCracken, M.E. ; Bellis, M. ; Meyer, C.A. ; et al.
Phys.Rev.C 81 (2010) 025201, 2010.
Inspire Record 840934 DOI 10.17182/hepdata.54967

We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi -) final-state topologies/ results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.

241 data tables
Table 1

Differential cross section as a function of COS(THETA(K)) for the centre-of-mass range 1.62-1.63 GeV.

Table 2

Differential cross section as a function of COS(THETA(K)) for the centre-of-mass range 1.63-1.64 GeV.

Table 3

Differential cross section as a function of COS(THETA(K)) for the centre-of-mass range 1.64-1.65 GeV.

More…

Charged hadron multiplicity fluctuations in Au+Au and Cu+Cu collisions from sqrt(s_NN) = 22.5 to 200 GeV

The PHENIX collaboration Adare, A. ; Adler, S.S. ; Afanasiev, S. ; et al.
Phys.Rev.C 78 (2008) 044902, 2008.
Inspire Record 785509 DOI 10.17182/hepdata.143616

A comprehensive survey of event-by-event fluctuations of charged hadron multiplicity in relativistic heavy ions is presented. The survey covers Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV, and Cu+Cu collisions sqrt(s_NN) = 22.5, 62.4, and 200 GeV. Fluctuations are measured as a function of collision centrality, transverse momentum range, and charge sign. After correcting for non-dynamical fluctuations due to fluctuations in the collision geometry within a centrality bin, the remaining dynamical fluctuations expressed as the variance normalized by the mean tend to decrease with increasing centrality. The dynamical fluctuations are consistent with or below the expectation from a superposition of participant nucleon-nucleon collisions based upon p+p data, indicating that this dataset does not exhibit evidence of critical behavior in terms of the compressibility of the system. An analysis of Negative Binomial Distribution fits to the multiplicity distributions demonstrates that the heavy ion data exhibit weak clustering properties.

86 data tables
Table 1a

Additional information containing number of events which were used to reconstruct the numvers matching to Figure 1 and 2.

Table 1b

Additional information containing number of events which were used to reconstruct the numvers matching to Figure 1 and 2.

Table 1c

Additional information containing number of events which were used to reconstruct the numvers matching to Figure 1 and 2.

More…

Electroproduction of $\phi(1020)$ mesons at $1.4\leq Q^2\leq$ 3.8 GeV$^2$ measured with the CLAS spectrometer

The CLAS collaboration Santoro, J.P. ; Smith, E.S. ; Garc con, M. ; et al.
Phys.Rev.C 78 (2008) 025210, 2008.
Inspire Record 781974 DOI 10.17182/hepdata.50913

Electroproduction of exclusive $\phi$ vector mesons has been studied with the CLAS detector in the kinematical range $1.6\leq Q^2\leq 3.8$ GeV$^{2}$, $0.0\leq t^{\prime}\leq 3.6$ GeV$^{2}$, and $2.0\leq W\leq 3.0$ GeV. The scaling exponent for the total cross section as $1/(Q^2+M_{\phi}^2)^n$ was determined to be $n=2.49\pm 0.33$. The slope of the four-momentum transfer $t'$ distribution is $b_{\phi}=0.98 \pm 0.17$ GeV$^{-2}$. The data are consistent with the assumption of s-channel helicity conservation (SCHC). Under this assumption, we determine the ratio of longitudinal to transverse cross sections to be $R=0.86 \pm 0.24$. A 2-gluon exchange model is able to reproduce the main features of the data.

5 data tables
Table 1

Axis error includes +- 18.6/18.6 contribution.

Table 2

Axis error includes +- 18.6/18.6 contribution.

Table 3

Axis error includes +- 18.6/18.6 contribution.

More…

pi0 photoproduction on the proton for photon energies from 0.675-GeV to 2.875-GeV.

Dugger, M. ; Ritchie, Barry G. ; Ball, J.P. ; et al.
Phys.Rev.C 76 (2007) 025211, 2007.
Inspire Record 749989 DOI 10.17182/hepdata.51855

Differential cross sections for the reaction $\gamma p \to p \pi^0$ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.675 to 2.875 GeV. The results reported here possess greater accuracy in the absolute normalization than previous measurements. They disagree with recent CB-ELSA measurements for the process at forward scattering angles. Agreement with the SAID and MAID fits is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been extended to 3 GeV. Resonance couplings have been extracted and compared to previous determinations.

45 data tables
Table 1

Differential cross section for indicent photon energy 675 MeV.

Table 2

Differential cross section for indicent photon energy 725 MeV.

Table 3

Differential cross section for indicent photon energy 775 MeV.

More…

Cascade production in the reactions gamma p --> K+ K+ (X) and gamma p --> K^+ K^+ pi- (X)

Guo, L. ; Weygand, D.P. ; Battaglieri, M. ; et al.
Phys.Rev.C 76 (2007) 025208, 2007.
Inspire Record 744487 DOI 10.17182/hepdata.31494

Photoproduction of the cascade resonances has been investigated in the reactions $\gamma p \to K^+ K^+ (X)$ and $\gamma p \to K^+ K^+ \pi^- (X)$. The mass split of the $\Xi$ doublet is measured to be $5.4\pm 1.8$ MeV/c$^2$, consistent with existing measurements. The differential (total) cross sections for the $\Xi^{-}$ have been determined for photon beam energies from 2.75 to 3.85 (4.75) GeV, and are consistent with a possible production mechanism of $Y^*\to K^+\Xi^-$ through a $t$-channel process. The reaction $\gamma p \to K^+ K^+ \pi^-[\Xi^0]$ has also been investigated in search of excited cascade resonances. No significant signal of excited cascade states other than the $\Xi^-(1530)$ is observed. The cross section results of the $\Xi^-(1530)$ have also been obtained for photon beam energies from 3.35 to 4.75 GeV.

47 data tables
Table 1

Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.79 Gev.

Table 2

Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.89 Gev.

Table 3

Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.99 Gev.

More…

Cross Sections for the $\gamma p \to K^{*0}\Sigma^+$ Reaction at $E_\gamma = 1.7 - 3.0$ GeV

The CLAS collaboration Hleiqawi, I. ; Hicks, K. ; Carman, D.S. ; et al.
Phys.Rev.C 75 (2007) 042201, 2007.
Inspire Record 742894 DOI 10.17182/hepdata.52647

Differential cross sections for the reaction $\gamma p \to K^{*0} \Sigma^+$ are presented at nine bins in photon energy in the range from 1.7 to 3.0 GeV. The \kstar was detected by its decay products, $K^+\pi^-$, in the CLAS detector at Jefferson Lab. These data are the first \kstar photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor $K^*$-quark couplings shows good agreement with the data in general, after adjusting the model's two parameters in a fit to our data. Disagreement between the data at forward angles and the global angle-energy fit to the model suggests that the role of scalar $\kappa$ meson exchange in $t$-channel diagrams should be investigated.

2 data tables
Table 1

Cross sections with total uncertainties.

Table 2

Cross sections with total uncertainties.


Separated structure functions for the exclusive electroproduction of K+ Lambda and K+ Sigma0 final states.

The CLAS collaboration Ambrozewicz, P. ; Carman, D.S. ; Feuerbach, R.J. ; et al.
Phys.Rev.C 75 (2007) 045203, 2007.
Inspire Record 732363 DOI 10.17182/hepdata.4994

We report measurements of the exclusive electroproduction of $K^+\Lambda$ and $K^+\Sigma^0$ final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions $\sigma_T$, $\sigma_L$, $\sigma_{TT}$, and $\sigma_{LT}$ were extracted from the $\Phi$- and $\epsilon$-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first $\sigma_L/\sigma_T$ separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from $0.5\leq Q^2\leq 2.8$ GeV$^2$ and invariant energy from $1.6\leq W\leq 2.4$ GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the $\Lambda$ and $\Sigma^0$ hyperons. These results provide an unprecedented data sample with which to constrain current and future models for the associated production of strangeness, which will allow for a better understanding of the underlying resonant and non-resonant contributions to hyperon production.

531 data tables
Table 1

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.6 to 1.7 GeV.

Table 2

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.70 to 1.75 GeV.

Table 3

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.75 to 1.80 GeV.

More…

First measurement of beam-recoil observables C(x) and C(z) in hyperon photoproduction.

The CLAS collaboration Bradford, R.K. ; Schumacher, R.A. ; Adams, G. ; et al.
Phys.Rev.C 75 (2007) 035205, 2007.
Inspire Record 732402 DOI 10.17182/hepdata.31496

Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions $\vec\gamma + p \to K^+ + \vec\Lambda$ and $\vec\gamma + p \to K^+ + \vec\Sigma^0$. The data were obtained using the CLAS detector at Jefferson Lab for center-of-mass energies $W$ between 1.6 and 2.53 GeV, and for $-0.85<\cos\theta_{K^+}^{c.m.}< +0.95$. For the $\Lambda$, the polarization transfer coefficient along the photon momentum axis, $C_z$, was found to be near unity for a wide range of energy and kaon production angles. The associated transverse polarization coefficient, $C_x$, is smaller than $C_z$ by a roughly constant difference of unity. Most significantly, the {\it total} $\Lambda$ polarization vector, including the induced polarization $P$, has magnitude consistent with unity at all measured energies and production angles when the beam is fully polarized. For the $\Sigma^0$ this simple phenomenology does not hold. All existing hadrodynamic models are in poor agreement with these results.

34 data tables
Table 1

Coefficients Cx and Cz for the reaction GAMMA P --> K+ LAMBDA for incident energy = 1.032 GeV and W = 1.679 GeV.

Table 2

Coefficients Cx and Cz for the reaction GAMMA P --> K+ LAMBDA for incident energy = 1.132 GeV and W = 1.734 GeV.

Table 3

Coefficients Cx and Cz for the reaction GAMMA P --> K+ LAMBDA for incident energy = 1.232 GeV and W = 1.787 GeV.

More…