Alpgard, K.
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Measurement of Anti-neutron Proton Total and Annihilation Cross-sections From 100-{MeV}/c to 500-{MeV}/c

The BROOKHAVEN-HOUSTON-PENNSYLVANIA STATE-RICE collaboration Armstrong, T. ; Chu, C. ; Clement, J. ; et al.
Phys.Rev.D 36 (1987) 659-673, 1987.
Inspire Record 253128 DOI 10.17182/hepdata.26943

Total and annihilation n¯p cross sections from 100 to 500 MeV/c are reported, the first such measurements with good statistics in this momentum range. These cross sections are well represented by A+B/p, where p is the incident antineutron momentum, and are in agreement with previous n¯p and p¯n measurements. A comparison of these cross sections with phenomenological potential model calculations is good overall. However, the microscopic quark model gives unsatisfactory predictions. The agreement between previous p¯p annihilation cross sections and n¯p cross sections above 300 MeV/c is excellent. The total n¯p cross section is lower than the total p¯p cross section in this momentum range. Both of these types of behavior are predicted by potential models. The anticipated availability of future p¯p data below 300 MeV/c should indicate whether these trends continue at lower momenta.

1 data table
Table 1

No description provided.


A SEARCH FOR NARROW STATES IN ANTI-NEUTRON PROTON TOTAL AND ANNIHILATION CROSS-SECTIONS NEAR ANTI-N N THRESHOLD

Armstrong, T. ; Chu, C. ; Clement, J.C. ; et al.
Phys.Lett.B 175 (1986) 383-386, 1986.
Inspire Record 236704 DOI 10.17182/hepdata.30241

The n̄p total and annihilation cross section have been measured from near N̄N threshold (1880 MeV) to 1940 MeV with RMS resolution ranging from 0.08 MeV (1880 MeV) to 6.7 MeV (1940 MeV). No significant narrow meson structures were seen, with 90% CL upper limits of 40–180 mb-MeV on σΓ for states with width less than our resolution. Combined with increasing unitarity bounds on σ as one approaches threshold, these limits confine widths of possible predicted states below 1900 MeV to less than ∼ 1 MeV.

1 data table
Table 1

No description provided.


Studies of $\bar{p} p \to \bar{n} n$ and $\bar{n} p$ Annihilation at Incident Momenta of 700-{MeV}/$c$ and 760-{MeV}/$c$

The Bombay-Chandigarh-Jammu-Tokyo collaboration Banerjee, S. ; Ganguli, S.N. ; Gurtu, A. ; et al.
Z.Phys.C 28 (1985) 163, 1985.
Inspire Record 217418 DOI 10.17182/hepdata.1974

Results are presented on the charge exchange reaction\(\bar pp \to \bar nn\) and\(\bar np\) annihilations from bubble chamber exposures to antiproton beam of momenta 700 and 760 MeV/c. The differential cross section of\(\bar pp \to \bar nn\) shows a forward spike followed by a clear dip bump structure. Total annihilation cross section of\(\bar np\) for average\(\bar n\) momentum of 700 MeV/c has been evaluated to be 55.4±2.2 mb. The multiplicity, Feynmanx andpT2 distributions for inclusive charged pions in\(\bar pp\) and\(\bar np\) annihilations are found to be similar. The emission of charged pions from\(\bar np\) annihilations are found to be consistent with thermodynamic models with temperature ∼110 MeV.

11 data tables
Table 1

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Table 2

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Table 3

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