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Near-threshold Photoproduction of Phi Mesons from Deuterium

Qian, X. ; Chen, W. ; Gao, H. ; et al.

Phys.Lett.B 696 (2011) 338-342, 2011.

Inspire Record 875788 DOI 10.17182/hepdata.56870

We report the first measurement of the differential cross section on $\phi$-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, $K^+$ and $K^-$ near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections $\frac{d\sigma}{dt}$ for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. This experiment establishes a baseline for a future experimental search for an exotic $\phi$-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of $\phi$ mesons.

1 data table

Table 1

Differential cross section as a function of ABS(T-TMIN).

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.

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Deeply virtual and exclusive electroproduction of omega mesons.

The CLAS collaboration Morand, L. ; Dore, D. ; Garcon, M. ; et al.

Eur.Phys.J.A 24 (2005) 445-458, 2005.

Inspire Record 681604 DOI 10.17182/hepdata.43499

The exclusive omega electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross sections were measured up to large values of the four-momentum transfer (-t < 2.7 GeV2) to the proton. The contributions of the interference terms sigma_TT and sigma_TL to the cross sections, as well as an analysis of the omega spin density matrix, indicate that helicity is not conserved in this process. The t-channel pi0 exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction gamma* p -> omega p, even for Q2 as large as 5 GeV2. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behaviour of the cross sections is nearly Q2-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit.

85 data tables

Table 1

Total cross sections and interference terms (TT and TL).

Table 2

Differential cross sections DSIG/DT for Q**2 = 1.725 GeV**2 and W = 2.77 GeV.

Table 3

Differential cross sections DSIG/DT for Q**2 = 1.752 GeV**2 and W = 2.48 GeV.

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Photoproduction of the omega meson on the proton at large momentum transfer.

The CLAS collaboration Battaglieri, M. ; Brunoldi, M. ; De Vita, R. ; et al.

Phys.Rev.Lett. 90 (2003) 022002, 2003.

Inspire Record 599053 DOI 10.17182/hepdata.19351

The differential cross section, $d\sigma/dt$ for $\omega$ meson exclusive photoproduction on the proton above the resonance region ($2.6<W<2.9$ GeV) was measured up to a momentum transfer $-t = 5$ GeV$^2$ using the CLAS detector at Jefferson Laboratory. The $\omega$ channel was identified by detecting a proton and $\pi^+$ in the final state and using the missing mass technique. While the low momentum transfer region shows the typical diffractive pattern expected from Pomeron and Reggeon exchange, at large $-t$ the differential cross section has a flat behavior. This feature can be explained by introducing quark interchange processes in addition to the QCD-inspired two-gluon exchange.

4 data tables

Table 1

Differential cross section in the energy region 3.20 to 3.38 GeV.

Table 2

Differential cross section in the energy region 3.38 to 3.56 GeV.

Table 3

Differential cross section in the energy region 3.56 to 3.74 GeV.

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Exclusive electroproduction of Phi mesons at 4.2-GeV.

The CLAS collaboration Lukashin, K. ; Smith, E.S. ; Adams, G.S. ; et al.

Phys.Rev.C 64 (2001) 059901, 2001.

Inspire Record 552246 DOI 10.17182/hepdata.38589

We studied the exclusive reaction e p --> e' p' phi using the phi --> K^+ K^- decay mode. The data were collected using a 4.2 GeV incident electron beam and the CLAS detector at Jefferson Lab. Our experiment covers the range in Q^2 from 0.7 to 2.2 GeV^2, and W from 2.0 to 2.6 GeV. Taken together with all previous data, we find a consistent picture of phi production on the proton. Our measurement shows the expected decrease of the t-slope with the vector meson formation time c Delta tau below 2 fm. At = 0.6 fm, we measure b_phi = 2.27 +- 0.42 GeV^-2. The cross section dependence on W as W^{0.2+-0.1} at Q^2 = 1.3 GeV^2 was determined by comparison with phi production at HERA after correcting for threshold effects. This is the same dependence as observed in photoproduction.

3 data tables

Table 1

Slope of the DSIG/DT distribution in different Q**2 regions.

Table 2

Cross section as a function of Q**2 and W.

Table 3

The differential cross section for exclusive PHI electroproduction off the photon, (TP=T-TMIN).

Cross sections for interaction of tritium nuclei with protons and elastic H-3 p scattering at momentum 5-GeV/c.

Abdullin, S.K. ; Blinov, A.V. ; Vanyushin, I.A. ; et al.

Sov.J.Nucl.Phys. 49 (1989) 106-107, 1989.

Inspire Record 287546 DOI 10.17182/hepdata.2229

None

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

REACTION OF QUASIELASTIC CHARGE EXCHANGE P HE-3 ---> N(F) P P P AT MEDIUM-ENERGIES. (IN RUSSIAN)

Blinov, A.V. ; Vanyushin, I.A. ; Grechko, V.E. ; et al.

Sov.J.Nucl.Phys. 47 (1988) 594, 1988.

Inspire Record 253277 DOI 10.17182/hepdata.9993

None

8 data tables

Table 1

N IS FAST IN LABORATORY SYSTEM. CUT FOR 'FAST' SELECTION WAS:. PLAB(P=3) > PMIN(P=3), WHERE PMIN IS DETERMINED FROM ALL EVENTS.

Table 2

N IS FAST IN LABORATORY SYSTEM. CUT FOR 'FAST' SELECTION WAS:. PLAB(P=3) > PMIN(P=4,5,6), WHERE PMIN IS DETERMINED FROM ALL EVENTS.

Table 3

No description provided.

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BACKWARD PION - DEUTERON ELASTIC SCATTERING FROM 1.75-GeV/c TO 3.1-GeV/c

Abramov, B.M. ; Ayrapetov, E.A. ; Bagdasaryan, L.S. ; et al.

Phys.Lett.B 189 (1987) 295-298, 1987.

Inspire Record 219757 DOI 10.17182/hepdata.40130

Measurements of the differential cross section for π − d elastic scattering in the backward angular region (−1 ⩽ cos θ cms ⩽ −0.98) are presented. These measurements were made at nine incident pion momenta P π ranging from 1.75 to 3.09 GeV/ c and at the largest values of q 2 [up to 7 (GeV/ c ) 2 ] ever reached experimentally; here q 2 is the momentum transfer squared. The differential cross section was found to decrease rapidly with increasing momentum d σ d Ω cms (180°) ∼ P −15.7 π , d σ d t ∼ (q 2 ) −12.8 . The data are compared with predictions of Regge and quark bag models.

1 data table

Table 1

Statistical errors only.