Difference spectra: Dominance of two-body cascades in antiproton-neutron annihilations at rest

Bridges, D.; Daftari, I. K.; Kalogeropoulos, T.E.; Debbe, R.; Fickinger, W.; Robinson, D. K.

doi:10.1103/physrevlett.56.215

Cited by 61 publications

(15 citation statements)

References 7 publications

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“…for 7^=0"^, /^^ = 2^"^ where we have the recently rediscovered ^A^//2(1520) by the ASTERIX Collaboration [10]. Its mass is better determined in the 3;r^ channel and the new mass, 1520 MeV, agrees well with that which was seen previously [11,12].…”

Section: Lir Inrvsupporting

confidence: 77%

“…In fact. Bridges et al [11] do see a peak in the 3K spectrum at 1480 MeV. In (K*co±K*p)/^, 7=2 and / = 1, the RBN is -2V3 and these would be new predictions, but as equally hard to form in the current experiments as the more stronger bound 7 = y state already discussed.…”

Section: Lir Inrvmentioning

confidence: 77%

“…For the G we do not know experimentally the pp.coco branching ratios, but their determination would be a good test of whether this candidate actually is a deuson. For Ax/fiilSlQ) the pp width is known to be dominant [11,12] as we expect. Note that deuson decays naturally violate flavor-symmetry predictions, but not isospin.…”

Section: Lir Inrvmentioning

confidence: 78%

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Possible large deuteronlike meson-meson states bound by pions

1991

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Section: Lir Inrvsupporting

confidence: 77%

Section: Lir Inrvmentioning

confidence: 77%

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Possible large deuteronlike meson-meson states bound by pions

1991

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“…(i) Momentum regime I (at rest): A study of channels of an antiproton colliding with a neutron near rest showed a majority of two-body intermediate states [24]. These intermediate states can then decay into channels including multiple pions; however, the decay of the intermediate states is not constrained to pion-only final states.…”

Section: B N-n In the Deuteronmentioning

confidence: 99%

Search for neutron-antineutron oscillations at the Sudbury Neutrino Observatory

Aharmim¹,

Ahmed²,

Anthony³

et al. 2017

Phys. Rev. D

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Tests on B − L symmetry breaking models are important probes to search for new physics. One proposed model with ΔðB − LÞ ¼ 2 involves the oscillations of a neutron to an antineutron. In this paper, a new limit on this process is derived for the data acquired from all three operational phases of the Sudbury Neutrino Observatory experiment. The search concentrated on oscillations occurring within the deuteron, and 23 events were observed against a background expectation of 30.5 events. These translated to a lower limit on the nuclear lifetime of 1.48 × 10 31 yr at 90% C.L. when no restriction was placed on the signal likelihood space (unbounded). Alternatively, a lower limit on the nuclear lifetime was found to be 1.18 × 10 31 yr at 90% C.L. when the signal was forced into a positive likelihood space (bounded). Values for the free oscillation time derived from various models are also provided in this article. This is the first search for neutron-antineutron oscillation with the deuteron as a target.

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“…10 A cut was made on the momentum of the recoiling proton p s to separate out the "spectator" events. For each multiplicity, they form the difference spectrum N(TT~) ~W(7r+), where N(7r ± ) is the number of events corresponding to inclusive n ± production.…”

Section: Pd-+ P S + (Pn)mentioning

confidence: 99%

Have QuasinuclearNN¯Bound States Been Discovered?

Dover

1986

Phys. Rev. Lett.

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It is suggested that a broad structure ^°(1480) recently observed in the reaction pn -* TT~X° -> 3TT~2TT + may be interpretable in terms of an unstable quasinuclear bound state of the (complex) nucleon-antinucleon (NN) potential. The observed mass, production branching ratio, and preference for the X°-* p°p° rather than TT + TT' decay mode are consistent with a quantum-number assignment /* c (/ c )»2 + + (0 + ). Prospects for finding the lower-lying 0 + + (0 + ) and 1'"(()-) members of the expected natural-parity quasinuclear band are discussed.PACS numbers: 14.40. Cs, 12.40.Qq, 13.25.+m, 13.75.Cs It has long been recognized that the AW system offers in principle an ideal entrance channel for the production of new types of jnesons, in addition to the usual quark-antiquark (QQ) configurations. These new mesons could include, Jor instance, quasinuclear (QN) bound .states of the AW potential, 1 "barycmium" states of Q 2 Q 2 structure, 2 "hybrids," i.e., QQg mesons 3 containing a dynamical gluon g, or glueballs.^ The search for new narrow mesons coupled to the AW system has been intense, but earlier evidence for the existence of such objects has not been confirmed in recent experiments 5 with intense p beams at LEAR (Low Energy Antiproton Ring at CERN).Unless there is a topological selection rule 6 suppressing direct decay of "baryonium" into mesons, on£ generally expects broad states. For instance, for AW quasinuclear mesons, the typical scale of width 1 is r =as 100 MeV, although narrower structures may occur in particular cases. 7 ' 8 New mesons, if they are highly unstable, are generally difficult to extract in a convincing way from AW annihilation data. Even if one picks a particular pion multiplicity n, there will often be numerous quasi two-body (QTB) reactions AW -• M X M 2 , leading directly to ordinary s= (77,17, p,a>} and p sss [€,8,A\,A2,D,f,B,H} mesons M x and M 2 . This "background" of QTB modes, interesting in its own right because of the connection between the underlying quark-gluon dynamics and observed selection rules, 9 masks the production of new mesons X in reactions such as NN-+ TTXOT yX.To minimize the QTB^and other backgrounds, one can choose the initial AW state and the particular final pion charge states in an optimum way. For instance, the pn or Tip initial states are more favorable in this regard than pp, since we thereby restrict attention to entrance channel isospin /=1, and thus eliminate / = 0 QTB modes. If we then choose n even or odd, i.e., G parity -(-)", we select 2/+1 ' 25+1 £ J = 33 S 1 or 31 S 0 initial AW states, respectively. We here assume that annihilation takes place from L = 0 states. Finally, we focus on annihilation modes containing the minimum number of 7r 0, s, since these contain the fewest QTB configurations. By explicit enumeration of QTB modes for each «, we have found that the reaction pn -• 3IT "~ 27r + is optimal for the study of new mesons X° via the process pn-+7T~X°. Note that X° can have isospin 0, 1, or 2. On the other hand, pp-> TT ± X T can only be u...

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Difference spectra: Dominance of two-body cascades in antiproton-neutron annihilations at rest

Cited by 61 publications

References 7 publications

Possible large deuteronlike meson-meson states bound by pions

Possible large deuteronlike meson-meson states bound by pions

Search for neutron-antineutron oscillations at the Sudbury Neutrino Observatory

Have QuasinuclearNN¯Bound States Been Discovered?

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