Axial Field Spectrometer
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High $p_T \gamma$ and $\pi^0$ Production, Inclusive and With a Recoil Hadronic Jet, in $p p$ Collisions at $\sqrt{s}=63$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Sov.J.Nucl.Phys. 51 (1990) 836-845, 1990.
Inspire Record 281284 DOI 10.17182/hepdata.48816

None

3 data tables
Table 1

Errors are combined statistical and systematic.

Table 2

Errors are combined statistical and systematic.

Table 3

Errors are combined statistical and systematic.


Direct Photon Plus Away - Side Jet Production in $p p$ Collisions at $s^1$/2 = 63-{GeV} and a Determination of the Gluon Distribution

The Axial Field Spectrometer collaboration Åkesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Z.Phys.C 34 (1987) 293, 1987.
Inspire Record 235690 DOI 10.17182/hepdata.15800

We have determined the double inclusive cross-section for opposite-side high-pT photons and away-side jets withθγ≈θjet≈90° produced inpp collisions at the CERN Intersecting Storage Rings at\(\sqrt s= 63\) GeV. Under the assumption that these events arise predominantly from the QCD gluon Compton process we have calculated the gluon structure function in the range 0.15≦x≦0.30 at an average square of the four-momentum transfer of 40 GeV2/c2. The data favour a soft gluon distribution in the proton.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


The Production of Prompt Positrons at Low Transverse Momentum Increases With the Square of the Associated Charged Multiplicity

The Axial Field Spectrometer collaboration Åkesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 192 (1987) 463-470, 1987.
Inspire Record 244887 DOI 10.17182/hepdata.30156

We have measured the production of prompt positrons in pp collisions at √ s = 63 GeV and y = 0 in the p T interval 0.12< p T <1.0 GeV/c. The results indicate that the production of positrons at low p T (<0.4 GeV/ c ) is proportional to the square of the mean multiplicity in the central region | y | < 1. Such a quadratic dependence is not expected from final-state sources such as hadronic bremsstrahlung or hadronic decays, but is natural in models where low mass electron pairs are produced by interactions of constituents created during the collision.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Search for Direct $\gamma$ Production at Low Transverse Momentum in 63-{GeV} $p p$ Collisions

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Rev.D 36 (1987) 2615, 1987.
Inspire Record 246577 DOI 10.17182/hepdata.23325

We have searched for direct photons of low PT (≤1.0 GeV/c) at θc.m.=90° in pp collisions at √s =63 GeV. We used two independent methods: direct detection in NaI crystals and conversion to e+e− pairs. No signal is observed; the photon spectrum is well described by the decay of hadrons. The result is consistent with a direct low-PT photon signal reported at √s =12 GeV, but excludes a rapid growth of soft-photon production with √s .

1 data table
Table 1

No description provided.


A Study of the Production of Two Direct Photons in $p p$ Collisions at the {CERN} {ISR}

The Axial Field Spectrometer collaboration Åkesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Z.Phys.C 32 (1986) 491-497, 1986.
Inspire Record 228954 DOI 10.17182/hepdata.15834

We have studied the processpp→γγ+X at\(\sqrt s= 63 GeV\) GeV in the central rapidity region. We report a positive signal at 96% C.L., a ratio γγ/e+e−=4.0±3.0 when the transverse momentum of each photon is above 2 GeV/c, and a cross-sectiondσ/dydMγγ=(5.5±2.7)×10−34 cm2/GeV when |y|<0.5,4<Mγγ<6 GeV.

1 data table
Table 1

No description provided.


Inclusive $\eta$ Production at Low Transverse Momentum in 63-{GeV} $p p$ Collisions at the {CERN} Intersecting Storage Rings

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 178 (1986) 447, 1986.
Inspire Record 230636 DOI 10.17182/hepdata.30230

The inclusive production of η-mesons in pp collisions at √ s =63GeV and ϑ CM =90° has been measured for p T <1.5GeV/c. The η/π ratio decreases from its previously measured asymptotic value of η/π ∼ 0.5 at high transverse momentum, to η/π ≈0.3 at P T = 750MeV/c and η/π ≈ 0.01 at P T =300MeV/c, in a way that consistent with phase-space considerations, e.g. m T scaling. The η/π ratio, integrated from 0.2–1.5 GeV/ c , is found to be η/π=0.07±0.055.

1 data table
Table 1

No description provided.


A MEASUREMENT OF ALPHA-ALPHA ELASTIC SCATTERING AT THE CERN ISR

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 152 (1985) 140-144, 1985.
Inspire Record 206315 DOI 10.17182/hepdata.30430

We present measurements of the αα elastic scattering differential cross section at √ s = 126 GeV in the range 0.05 ⩽ ‖ t ‖

3 data tables
Table 1

ERRORS ARE STATISTICAL ONLY.

Table 2

EXPONENTIAL FIT TO CROSS SECTION BELOW T = 0.075 GEV**2.

Table 3

OPTICAL THEOREM CALCULATION OF THE TOTAL CROSS SECTION ASSUMING RHO IS ZERO.


Multiplicity Distributions in $p \alpha$ and $\alpha \alpha$ Collisions in the {CERN} {ISR}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 119 (1982) 464, 1982.
Inspire Record 179518 DOI 10.17182/hepdata.6665

Measurements of charged particle multiplicity distributions in the central rapidity region in p-p and p-α, and α-α collisions are reported. They are better fitted to the “wounded nucleon” than to the “gluon string” model. The average transverse momenta, for all three reactions, are identical (and almost independent of multiplicity) up to very high multiplicities.

2 data tables
Table 1

THE FIRST PP DATA IS AT 44 GEV, THE SECOND AT 63 GEV.

Table 2

No description provided.


Anti-Baryon Production in the Central Region at the {ISR}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Nucl.Phys.B 246 (1984) 1-11, 1984.
Inspire Record 199804 DOI 10.17182/hepdata.33869

Using annihilation in a calorimeter as a trigger on antiprotons, we have measured the relative production cross sections of p , Λ and Ξ at y∼0 in the transverse momentum range 1 to 2 GeV/ c in pp collisions at √ s =63 GeV. We investigate correlations between the antibaryons and associated produced particles, and find evidence for local baryon number conservation.

1 data table
Table 1

No description provided.


Inclusive Vector - Meson Production in the Central Region of $p p$ Collisions at $\sqrt{s}=63$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Nucl.Phys.B 203 (1982) 27, 1982.
Inspire Record 176735 DOI 10.17182/hepdata.34135

Production of ϱ 0 , K ∗0 , K ∗0 , and φ have been measured in proton-proton collisions at the CERN Intersecting Storage Rings (ISR) at low p T in the central region. The transverse mass spectra are well described by exp (− aμ T ), with a = −6.4±0.2 GeV −1 . The cross sections for d σ/ d y| y=0 are 6.5±0.8±1.2 mb for ϱ 0 , 1.9±0.3±0.3 mb for K ∗) , 1.9±03±03 mb for K ∗0 , and 60.±0.12±0.13 mb for φ , where the first error is statistical and the second is sytematic.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Large Transverse Momentum Particle Production in $\alpha \alpha$ and $p p$ Collisions at the {CERN} {ISR}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Nucl.Phys.B 209 (1982) 309-320, 1982.
Inspire Record 178882 DOI 10.17182/hepdata.34016

The production of charged hadrons with high p T in αα collisions at √ s =126 GeV and pp collisions at √ s =31 and 63 GeV is compared, and the structure of the events associated with the high- p T particles is studied. The probability of finding associated particles close to the trigger particle increases strongly between √ s =31 and 63 GeV for pp collisions. For p T >2.5GeV/ c the αα/pp cross section ratio at the same energy per nucleon is measured to be 18.7 ± 2.0, to be compared with A 2 = 16, and a higher associated multiplicity is observed for αα.

1 data table
Table 1

FIRST PP DATA IS AT SQRT(S)=31 AND THE SECOND PP DATA IS AT 63 GEV.


A Comparison of Hadron Production in $p \bar{p}$ and $p p$ Collisions in the Central Region at $\sqrt{s}=53$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Nucl.Phys.B 228 (1983) 409-423, 1983.
Inspire Record 190653 DOI 10.17182/hepdata.37131

We have studied the inclusive production of the hadrons π ± , K ± , p, p , Λ, Λ , ρ and ⋉ in the central region at the ISR s = 53 GeV , in both pp and p p collisions. Differences are observed only for K ± , p, and p production. We then study also correlations between low- p T pp and p p pairs in the two types of collisions, separating the contribution from baryon pair production and from the incident particles (stopping protons). We observe a positive correlation between two stopping protons; between the production of two pairs, and between a stopping proton and a pair production, there are negative correlations.

1 data table
Table 1

No description provided.


A Comparison of $\bar{p} p$ and $p p$ Interactions in the Central Region at $\sqrt{s}=53$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 108 (1982) 58-62, 1982.
Inspire Record 168036 DOI 10.17182/hepdata.31012

The inclusive production cross sections of pions, kaons, protons, and antiprotons in p p and pp interactions at √ s =53 GeV are compared in the kinematic range | y | < 0.8 and p T < 1.5 GeV/ c . We observe differences in the K + /K − and p /p ratios for the two data samples. Although the bulk of the particles are produced with the same momentum and rapidity distributions in p p and pp collisions, we observe difference in these distributions for produced protons and antiprotons.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Direct Evidence for the Emergence of Jets in Events Triggered on Large Transverse Energy in $p p$ Collisions at $\sqrt{s}=63$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 118 (1982) 185-192, 1982.
Inspire Record 179517 DOI 10.17182/hepdata.30854

We present data obtained from a 1.7 sr hadron calorimeter, triggered on transverse energy, in pp collisions at s =63 GeV at the CERN-ISR. From the change in the distribution of energy in the calorimeter, we extract the cross section for two-constituent hard scattering for p T between 6 and 14 GeV at y = 0. The decrease of this jet cross section over this p T range is consistent with exp (− bp T ), with b = (1.02 ± 0.09) GeV −1 . The slope and normalization of the cross section agree well with a QCD motivated Monte Carlo model. The ratio between jet and single particle cross sections [ dσ JET / dp T )/( dσ π 0 / dp T )]| y = 0 changes from about 200 at 6 GeV to about 1500 at 14 GeV.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Bose-einstein Correlations in $\alpha \alpha$, $p p$ and $p \bar{p}$ Interactions

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 129 (1983) 269-272, 1983.
Inspire Record 190654 DOI 10.17182/hepdata.30661

Bose-Einstein correlations between pions produced in the central region of rapidity in αα, pp and p p interactions have been studied at the ISR. The parameters r and τ c -often interpreted as the radius and depth of the π-emitting region - are found to be independent of incident particle type but to depend on the mean charged multiplicity. In high multiplicity events, the pions appear to originate from a larger space-time region.

12 data tables
Table 1

FOR DEFINITION OF R++ SEE PAPER.

Table 2

FOR DEFINITION OF R++ SEE PAPER.

Table 3

FOR DEFINITIONS OF R++ AND TAU*C SEE PAPER.

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High $p_T$ Direct Photon Production at 11-degrees in $p p$ Collisions at $\sqrt{s}=63$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 123 (1983) 367-372, 1983.
Inspire Record 188929 DOI 10.17182/hepdata.30744

The production of direct photons has been measured relative to π 0 's in the rapidity range 2.00 < y < 2.75 in pp collisions at s = 63 GeV at the CERN Intersecting Storage Rings. The γ/π 0 ratio increases from ⪅2% at p T = 1.5 GeV/ c to ∼8% at p T = 4.25 GeV/ c , similar to the value observed near 90°. The results indicate no strong enhancement of single-photon production due to quark bremsstrahlung in this kinematic region.

1 data table
Table 1

No description provided.


Hadron and Hadron Pair Production at Large Transverse Momentum in $p \bar{p}$ and $p p$ Interactions at the {ISR}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 121 (1983) 439-444, 1983.
Inspire Record 182425 DOI 10.17182/hepdata.30813

We have measured the production of one and two large transverse momentum hadrons in p p and pp interactions in the range 2 < p T < 6 GeV/ c for the central rapidity region |y| < 0.9 at s = 63 and 31 GeV . No statistically significant difference between p p and pp collisions is observed. The results are in accordance with lowest order QCS perturbative calculations and rule out a large contribution of Constituent Interchange Model (CIM), di-quark of quark-fusion subprocesses in this kinematic range.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


The Dominance of Jets at Large Transverse Energy in a Full Azimuth Hadron Calorimeter at {ISR} Energies

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 128 (1983) 354-360, 1983.
Inspire Record 190652 DOI 10.17182/hepdata.30701

Events with a large transverse energy in a calorimeter with full azimuthal coverage and | y | < 0.9 have been investigated in pp collisions at √ s = 30, 45, and 63 GeV. A striking change in the event structure, corresponding to a clear emergence of high- p T jets, is observed at √ s = 63 and 45 GeV in the region between 25 and 35 GeV in transverse energy. At √ s = 30 GeV, the data extend to E T ∼ 20 GeV, but no such change in the event structure is observed.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


A comparison of direct photon, $\pi^0$, and $\eta$ production in $p\bar{p}$p and $pp$ interactions at the CERN ISR

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 158 (1985) 282-288, 1985.
Inspire Record 213984 DOI 10.17182/hepdata.30391

We have measured the production of direct photons, π 0 's, and η's in p p and pp collisions at √ s =53 GeV in the range 2≈ p T ≈6 GeV/ c for the central rapidity region | y | 0.4. No statistically significant difference between pp̄ and pp interactions is observed.

5 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Production of $\pi^0$ and Eta0 at 11-degrees in $p p$ Collisions at $\sqrt{s}=63$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Z.Phys.C 18 (1983) 5, 1983.
Inspire Record 188928 DOI 10.17182/hepdata.16326

The inclusive π0 production cross-section and the η/π0 ratio have been measured inpp collisions at\(\sqrt s= 63 GeV\) at the CERN Intersecting Storage Rings in the rapidity range 2.00<y<2.75. The π0 cross-section exhibits a strongy-dependence and falls more steeply as a function ofpT, compared with the cross-section measured aty∼0. We find a value of 0.46±0.07 for the η/π0 ratio with no significantpT dependence over the range 2.0<pT<4.0 GeV/c.

2 data tables
Table 1

No description provided.

Table 2

No description provided.