HEPData Search

Showing 10 of 225 results

First observations of Pontecorvo reactions with a recoiling neutron

The Crystal Barrel collaboration Amsler, C. ; Armstrong, D.S. ; Augustin, I. ; et al.

Z.Phys.A 351 (1995) 325-331, 1995.

Inspire Record 407110 DOI 10.17182/hepdata.16505

We report the first observations of Pontecorvo reactions of the type ¯pd →Xn. We fully reconstruct the outgoing meson and, for antiprotons stopped in liquid deuterium, we measure: BR(¯pd→π0)=(7.03±0.72)×10−6, BR(¯pd→ηn)=(3.19+0.48)×10−6, BR(¯pd→ωn)=(22.8+4.1)×10−6, BR(¯pd→η′n)14×10−6 (at 95% confidence level). Assuming charge independence, our result for¯ pd→π0n is compatible with measurements of the only other observed Pontecorvo reaction ¯pd → π−p. The experimental ratios between the above branching ratios are in fair agreement with both the statistical model and dynamical two-step models (assumingN¯ N annihilation into two mesons, with subsequent absorption of one meson on the remaining nucleon). This agreement suggests that there may be appreciable rates for Pontecorvo reactions producing final state mesons with masses above 1 GeV.

1 data table

Table 1

No description provided.

Nuclear structure function in carbon near x = 1

The BCDMS collaboration Benvenuti, A.C. ; Bollini, D. ; Camporesi, T. ; et al.

Z.Phys.C 63 (1994) 29-36, 1994.

Inspire Record 374300 DOI 10.17182/hepdata.48235

Data from deep inelastic scattering of 200 GeV muons on a carbon target with squared four-momentum transfer 52 GeV2≤Q2≤200 GeV2 were analysed in the region of the Bjorken variable close tox=1, which is the kinematic limit for scattering on a free nucleon. At this value ofx, the carbon structure function is found to beF2C≈1.2·10−4. Thex dependence of the structure function forx>0.8 is well described by an exponentialF2C∞exp(−sx) withs=16.5±0.6.

5 data tables

Table 1

No description provided.

Table 2

Multiplicative factors by which F2 has to be multiplied or divided to allow for a systematic uncertainty in detector resolution.

Table 3

Multiplicative factors by which F2 has to be multiplied or divided to allow for a systematic uncertainty in the beam energy.

More…

The Search for heavy pentaquark exotic baryons with hidden strangeness in the p + N ---> (p Phi) + N and p + N ---> (Lambda (1520) K+) + N reactions at E(p) = 70-GeV

The SPHINX collaboration Dorofeev, V.A. ; Golovkin, S.V. ; Kozhevnikov, A.P. ; et al.

Phys.Atom.Nucl. 57 (1994) 227-237, 1994.

Inspire Record 385732 DOI 10.17182/hepdata.40688

None

2 data tables

Table 1

No description provided.

Table 2

The upper limits for production of EXOTIC-NUCLEON with narrow width (<50 MeV). Linear A-dependence of the cross section is assumed.

Search for N (phi) (1960) baryon

The SPHINX collaboration Balats, M.Ya. ; Belyaev, I.M. ; Dorofeev, V.A. ; et al.

Z.Phys.C 61 (1994) 399-405, 1994.

Inspire Record 376444 DOI 10.17182/hepdata.14371

In the experiments at the SPHINX facility in the 70 GeV proton beam of the IHEP accelerator the diffractive production reactionsp+N→[Σ(1385)0K+] +N andp+N→[Σ(1385)0K+]+N+ (neutral particles) were studied. In the effective mass spectra of the [Σ(1385)0K+] system in these processes there were no signals from the anomalously narrow baryon stateNϕ (1960) which had been observed earlier in the measurement at the BIS-2 setup.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Investigation of diffraction processes p + N ---> (p p anti-p) + N and p + N ---> (p p anti-p pi0) + N at E(p) = 70-Gev

The SPHINX collaboration Vavilov, D.V. ; Viktorov, V.A. ; Golovkin, S.V. ; et al.

Phys.Atom.Nucl. 57 (1994) 1970-1973, 1994.

Inspire Record 365726 DOI 10.17182/hepdata.40602

None

1 data table

Table 1

No description provided.

Differential cross-sections and analyzing powers for anti-p p ---> pi- pi+ and K- K+ from 360-MeV/c to 1550-MeV/c

Hasan, A. ; Bugg, D.V. ; Hall, J.R. ; et al.

Nucl.Phys.B 378 (1992) 3-51, 1992.

Inspire Record 339576 DOI 10.17182/hepdata.6880

Analysing powers and differential cross sections for p p → π − π + and p p → K − K + have been measured over the full angular range using a polarised target at LEAR at 20 beam momenta from 360 to 1550 MeV/ c . Discrepancies in the normalisation of earlier d σ/ d Ω data at low momenta are clarified. Above 1000 MeV/ c , A 0N results confirm values close to +1 over most of the angular range for both reactions, in excellent agreement with earlier data of lower statistics. Below 1000 MeV/ c , where the analysing power is measured for the first time, large variations of A 0N with energy and angle are present.

84 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

First measurement of D (0n 0n) in anti-p p elastic scattering

Kunne, R.A. ; Beard, C.I. ; Birsa, R. ; et al.

Phys.Lett.B 261 (1991) 191-196, 1991.

Inspire Record 316076 DOI 10.17182/hepdata.29400

The depolarization parameter D onon in p p elastic scattering has been measured at LEAR for thirteen momenta between 679 and 1550 MeV/c in the backward angular region. Striking disagreement with theoretical models is observed.

10 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Measurement of $d \sigma / d \Omega$ and A(on) in $\bar{p} p$ Elastic Scattering Between 497-{MeV}/$c$ and 1550-{MeV}/$c$

Kunne, R.A. ; Beard, C.I. ; Birsa, R. ; et al.

Nucl.Phys.B 323 (1989) 1-36, 1989.

Inspire Record 267175 DOI 10.17182/hepdata.48676

Measurements have been made of the differential cross section and asymmetry A on for p p elastic scattering at 15 incident momenta between 497 MeV/ c and 1550 MeV/ c . The angular range where both particles have enough energy to traverse target and setup has been covered. The results are compared with predictions of various N N potential models. None of these models fully explains the present results, although the general trend of the data is predicted correctly.

16 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Polarization at Small Angles in Anti-proton - Carbon Elastic Scattering at {LEAR} Energies

The SING collaboration Martin, A. ; Birsa, R. ; Bos, K. ; et al.

Nucl.Phys.A 487 (1988) 563-590, 1988.

Inspire Record 261245 DOI 10.17182/hepdata.37001

A double-scattering experiment of antiprotons on carbon has been carried out at the Low-Energy Antiproton Ring (LEAR) at CERN, to measure the polarization parameter A p C in antiproton-carbon elastic scattering at small angles. The polarization parameter has been inferred from the azimuthal distribution of the antiprotons after the second scattering. Data have also been collected with a liquid-hydrogen target as the second scatterer, thus allowing the sign of A p C to be determined. The experiment has been performed at two momenta of the extracted antiproton beam, 800 and 1100 MeV/c. A small positive value of the polarization has been observed, compatible with energy independence and a linear increase with the momentum transfer q . Parametrizing A p C as a c q , we get a c = +0.72 0.10 +0.09 ( GeV / c ) −1 . This result is compared with potential model predictions for N̄N amplitudes through a Glauber theory calculation.

6 data tables

Table 1

THETA1(RF=LAB)=8 DEG, THETA POINTED IN TABLE IS THE SECOND SCATTERING ANGLE.

Table 2

THETA1(RF=LAB)=5 DEG, THETA POINTED IN TABLE IS THE SECOND SCATTERING ANGLE.

Table 3

THETA1(RF=LAB)=8 DEG, THETA POINTED IN TABLE IS THE SECOND SCATTERING ANGLE.