A Study of the fragmentation of quarks in e- p collisions at HERA

The H1 collaboration Aid, S. ; Andreev, V. ; Andrieu, B. ; et al.
Nucl.Phys.B 445 (1995) 3-21, 1995.
Inspire Record 394793 DOI 10.17182/hepdata.44978

Deep inelastic scattering (DIS) events, selected from 1993 data taken by the H1 experiment at HERA, are studied in the Breit frame of reference. The fragmentation function of the quark is compared with those of \ee data. It is shown that certain aspects of the quarks emerging from within the proton in \ep interactions are essentially the same as those of quarks pair-created from the vacuum in \ee annihilation. The measured area, peak position and widthof the fragmentation function show that the kinematic evolution variable, equivalent to the \ee squared centre of mass energy, is in the Breit frame the invariant square of the four-momentum transfer. We comment on the extent to which we have evidence for coherence effects in parton showers.

5 data tables match query

Distribution of the cosine of the Breit frame polar angle for data with the Breit frame energy flow selection. Statistical errors only.

Distribution of the cosine of the Breit frame polar angle for data before the Breit frame energy flow selection. Statistical errors only.

The fragmentation function for the current hemisphere of the Breit frame. Data are Breit frame energy flow selected only. Statistical errors only.

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Measurement of dijet cross sections in e p interactions with a leading neutron at HERA.

The H1 collaboration Aktas, A. ; Andreev, V. ; Anthonis, T. ; et al.
Eur.Phys.J.C 41 (2005) 273-286, 2005.
Inspire Record 669251 DOI 10.17182/hepdata.46199

Measurements are reported of the production of dijet events with a leading neutron in ep interactions at HERA. Differential cross sections for photoproduction and deep inelastic scattering are presented as a function of several kinematic variables. Leading order QCD simulation programs are compared with the measurements. Models in which the real or virtual photon interacts with a parton of an exchanged pion are able to describe the data. Next-to-leading order perturbative QCD calculations based on pion exchange are found to be in good agreement with the measured cross sections. The fraction of leading neutron dijet events with respect to all dijet events is also determined. The dijet events with a leading neutron have a lower fraction of resolved photon processes than do the inclusive dijet data.

3 data tables match query

Differential e p photoproduction cross section as a function of the jet transverse energy.

Differential e p DIS cross section as a function of the jet transverse energy.

Ratio of cross section for dijet production with a leading neutron to that for inclusive dijet production as a function of the jet transverse energy.


Observation of an ABC effect in proton-proton collisions

Dymov, S. ; Hartmann, M. ; Kacharava, A. ; et al.
Phys.Rev.Lett. 102 (2009) 192301, 2009.
Inspire Record 812534 DOI 10.17182/hepdata.51593

The cross section for inclusive multipion production in the pp->ppX reaction was measured at COSY-ANKE at four beam energies, 0.8, 1.1, 1.4, and 2.0 GeV, for low excitation energy in the final pp system, such that the diproton quasi-particle is in the 1S0 state. At the three higher energies the missing mass Mx spectra show a strong enhancement at low Mx, corresponding to an ABC effect that moves steadily to larger values as the energy is increased. Despite the missing-mass structure looking very different at 0.8 GeV, the variation with Mx and beam energy are consistent with two-pion production being mediated through the excitation of two Delta(1232) isobars, coupled to S-- and D-- states of the initial pp system.

4 data tables match query

The P P --> P P X differential cross section as a function of the square ofthe missing mass (X) at incident beam energy of 0.8 GeV.

The P P --> P P X differential cross section as a function of the square ofthe missing mass (X) at incident beam energy of 1.1 GeV.

The P P --> P P X differential cross section as a function of the square ofthe missing mass (X) at incident beam energy of 1.4 GeV.

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Measurement of the A-dependence of deep inelastic electron scattering

Gomez, J. ; Arnold, R.G. ; Bosted, Peter E. ; et al.
Phys.Rev.D 49 (1994) 4348-4372, 1994.
Inspire Record 359103 DOI 10.17182/hepdata.22575

Cross sections for deep-inelastic electron scattering from liquid deuterium, gaseous He4, and solid Be, C, Al, Ca, Fe, Ag, and Au targets were measured at the Stanford Linear Accelerator Center using electrons with energies ranging from 8 to 24.5 GeV. These data cover a range in the Bjorken variable x from 0.089 to 0.8, and in momentum transfer Q2 from 2 to 15 (GeV/c)2. The ratios of cross sections per nucleon (σAσd)is for isoscalar nuclei have been extracted from the data. These ratios are greater than unity in the range 0.1<x<0.3, while for 0.3<x<0.8 they are less than unity and decrease logarithmically with atomic weight A, or linearly with average nuclear density. No Q2 dependence in the ratios was observed over the kinematic range of the data. These results are compared to various theoretical predictions.

1 data table match query

Additional overall systematic error of 1 pct plus a target to target systematic error of 0.9 pct.


Production Spectra of pi+-, K+-, rho+- at Large Angles in Proton Proton Collisions in the CERN Intersecting Storage Rings

The British-Scandinavian collaboration Alper, B. ; Böggild, H. ; Booth, P. ; et al.
Nucl.Phys.B 100 (1975) 237-290, 1975.
Inspire Record 99735 DOI 10.17182/hepdata.8506

Results are given on the inclusive production of charged pions, kaons, and nucleons, in proton-proton collisions at c.m. energies from √ s = 23 to 63 GeV at large angles and for the transverse momentum range 0.1 < p T < 4.8 GeV/ c . The dependence of the production spectra on the collision energy √ s , the transverse momentum p T , and the longitudinal rapidity is discussed.

1 data table match query

Axis error includes +- 6.0/6.0 contribution (NORMALIZAION ERROR - THE LARGEST SYSTEMATICS).


Inelastic Diffractive Scattering at the CERN ISR

The CHLM collaboration Albrow, M.G. ; Bagchus, A. ; Barber, D.P. ; et al.
Nucl.Phys.B 108 (1976) 1-29, 1976.
Inspire Record 3424 DOI 10.17182/hepdata.8494

The properties of the diffractive peak observed in the mass spectra of systems recoiling against observed high-momentum protons emerging from pp collisions at the CERN ISR have been investigated. The cross sections in this peak have been found to have a steep t dependence which flattens out as | t | increases. The high mass side of the peak varies approximately as 1/ M 2 (where M is the missing mass of the recoiling system) and scales well in terms of the variable M 2 / s . The position of the maximum has been observed to move to lower values of M 2 / s as the kinematic boundary of this variable decreases with increasing s . The measured cross sections, integrated up to M 2 / s =0.05, rise by (15±5)% over the s range 549 to 1464 GeV 2 .

1 data table match query

No description provided.


Experimental Studies of the Neutron and Proton Electromagnetic Structure Functions

Bodek, A. ; Breidenbach, Martin ; Dubin, D.L. ; et al.
Phys.Rev.D 20 (1979) 1471-1552, 1979.
Inspire Record 140185 DOI 10.17182/hepdata.4325

We have carried out an experimental study of the neutron and proton deep-inelastic electromagnetic structure functions. The structure functions were extracted from electron-proton and electron-deuteron differential cross sections measured in three experiments spanning the angles 6°, 10°, 15°, 18°, 19°, 26°, and 34°. We report primarily on the large-angle (15°-34°) measurements. Neutron cross sections were extracted from the deuteron data using an impulse approximation. Our results are consistent with the hypothesis that the nucleon is composed of pointlike constituents. The variation of the cross section with angle suggests that the hypothetical constituents have spin ½. The data for σnσp, the ratio of the neutron and proton differential cross sections, are in the range 0.25 to 1.0, and are within the limits imposed by the quark model. Detailed studies of the structure functions were made for a range of the scaling variable ω from ω=1.3 to ω=10.0, and for a range of invariant four-momentum transfer Q2 from 1.0 to 20.0 GeV2. These studies indicate that the structure functions approximately scale in the variable ω, although significant deviations from scaling in ω are apparent in the region 1.3<ω<3.3. These deviations from scaling are in the same direction and of similar magnitude for both neutron and proton. The interpretation of the data in terms of various theoretical models is discussed.

1 data table match query

No description provided.


Extraction of the Structure Functions and R=Sigma-L/Sigma-T from Deep Inelastic e p and e d Cross-Sections

Riordan, E.M. ; Bodek, A. ; Breidenbach, Martin ; et al.
SLAC-PUB-1634, 1975.
Inspire Record 100687 DOI 10.17182/hepdata.591

None

1 data table match query

No description provided.


LONGITUDINAL CORRELATIONS BETWEEN PIONS IN INCIDENT HADRON FRAGMENTATION REGION IN K- p INTERACTIONS AT 32-GeV/c

Bumazhnov, V.A. ; Buschbeck, B. ; Cochet, C. ; et al.
IFVE-81-112, 1981.
Inspire Record 168441 DOI 10.17182/hepdata.41430

None

1 data table match query

DISTRIBUTION IS PRESENTED IN THE BEAM FRAGMENTATION REGIONS.


Measurements of single diffraction at s**(1/2) = 630-GeV: Evidence for a nonlinear alpha(t) of the Pomeron

The UA8 collaboration Brandt, A. ; Erhan, S. ; Kuzucu, A. ; et al.
Nucl.Phys.B 514 (1998) 3-44, 1998.
Inspire Record 449347 DOI 10.17182/hepdata.32682

We report measurements of the inclusive differential cross section for the single-diffractive reactions: p + pbar --> p + X and p + pbar --> X + pbar at sqrt(s) = 630 GeV, in the momentum transfer range, 0.8 < -t < 2.0 GeV^2 and final state Feynman-x > 0.90. Based on the assumption of factorization, several new features of the Pomeron Flux Factor are determined from simultaneous fits to our UA8 data and lower energy data from the CHLM collaboration at the CERN-Intersecting Storage Rings. Prominent among these is that the effective Pomeron Regge trajectory requires a term quadratic in t, with coefficient, a'' = 0.079 +- 0.012 GeV^{-4}. We also show that the data require a Pomeron-proton cross section that first decreases with increasing diffractive mass (corresponding to the PPR term in the triple-Regge expansion) and then increases at larger mass (the PPP term), similar to real particle total cross sections. We measure the product, (K x sigma0) = 0.72 +- 0.10 mb/GeV^2, where K is the normalization constant of the Pomeron Flux Factor in the proton and sigma0 is the scale constant in the Pomeron-proton total cross section. Finally, we report the occurence of ``beam jets'' in the Pomeron direction in the rest frame of the diffractive system.

3 data tables match query

The average energy flow event in the C.M. frame of the system X for different values of S prime (the invariant Squark mass of the X system).

The average energy flow event in the C.M. frame of the system X for different values of S prime (the invariant Squark mass of the X system).

The average energy flow event in the C.M. frame of the system X for different values of S prime (the invariant Squark mass of the X system).