HEPData Search

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Deep inelastic scattering with leading protons or large rapidity gaps at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.

Nucl.Phys.B 816 (2009) 1-61, 2009.

Inspire Record 804915 DOI 10.17182/hepdata.52860

The dissociation of virtual photons, $\gamma^{\star} p \to X p$, in events with a large rapidity gap between $X$ and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA. The data cover photon virtualities $Q^2>2$ GeV$^2$ and $\gamma^{\star} p$ centre-of-mass energies $40<W<240$ GeV, with $M_X>2$ GeV, where $M_X$ is the mass of the hadronic final state, $X$. Leading protons were detected in the ZEUS leading proton spectrometer. The cross section is presented as a function of $t$, the squared four-momentum transfer at the proton vertex and $\Phi$, the azimuthal angle between the positron scattering plane and the proton scattering plane. It is also shown as a function of $Q^2$ and $\xpom$, the fraction of the proton's momentum carried by the diffractive exchange, as well as $\beta$, the Bjorken variable defined with respect to the diffractive exchange.

48 data tables

Table 1

The differential cross section DSIG/DT for the LRG and the LPS data samples.

Table 2

The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).

Table 3

The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).

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rivet Analysis
Evidence of a broad structure at an invariant mass of 4.32- GeV/c**2 in the reaction e+ e- ---> pi+ pi- psi(2S) measured at BaBar

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Bona, M. ; et al.

Phys.Rev.Lett. 98 (2007) 212001, 2007.

Inspire Record 729388 DOI 10.17182/hepdata.19344

We present a measurement of the cross section of the process $e^+e^-\to\pi^+pi^-\psi(2S)$ from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the PEP-II $e^+e^-$ storage rings. The study is based on 298 fb$^{-1}$ of data recorded with the BaBar detector. A structure is observed in the cross-section not far above threshold, near 4.32 GeV. We also investigate the compatibility of this structure with the Y(4260) previously reported by this experiment.

1 data table

Table 1

The measured c.m. energy dependence of the cross section with statistical errors only.. Bins with no recorded data are shown as a 'dash'.

Observation of D0 ---> K+ pi- rho0 produced in interactions of 40-GeV - 70-GeV neutrons with hydrogen, carbon and aluminum

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.

JINR-P1-90-595, 1990.

Inspire Record 305481 DOI 10.17182/hepdata.38714

None

2 data tables

Table 1

NUCLEUS IS P, C, AL.

Table 2

No description provided.

Search for narrow baryonia

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.

575-576, 1990.

Inspire Record 299495 DOI 10.17182/hepdata.39385

None

1 data table

Table 1

No description provided.

Search for Narrow Baryonia With Negative and Positive Strangeness

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.

Z.Phys.C 47 (1990) 533-537, 1990.

Inspire Record 285796 DOI 10.17182/hepdata.15148

A search for baryonia with negative and positive strangeness decaying respectively into$\Lambda+ \bar p + pions$ and$\bar \Lambda+ p + pions$ has been carried out in a neutron beam with a mean momentum of ≅40 GeV/c in an experiment performed at the Serpukhov accelerator. There is a strong indication of the existence of these baryonia. The following four charge states are observed for negative and positive strangeness: neutral, negative, positive and doubly charged. Their mean mass is 3055±25 MeV/c2 and the width Γ≦36±15 MeV/c2. The data show that the isotopic spin of the baryonia is ≧3/2. The baryonia production cross sections in the acceptable kinematic regionXF≧0.2 andPT≦1 GeV/c times the branching ratios of the observed decays are of the order of 1 μb per nucleon.

1 data table

Table 1

No description provided.