We present measurements of the total production rates and momentum distributions of the charmed baryon $\Lambda_c^+$ in $e^+e^- \to$ hadrons at a center-of-mass energy of 10.54 GeV and in $\Upsilon(4S)$ decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in $e^+e^- \to c\bar{c}$ events, allowing direct studies of $c$-quark fragmentation. We measure a momentum distribution for $\Lambda_c^+$ baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of $\left< x_p \right> = 0.574\pm$0.009 and a total rate of $N_{\Lambda c}^{q\bar{q}} = 0.057\pm$0.002(exp.)$\pm$0.015(BF) $\Lambda_c^+$ per hadronic event, where the experimental error is much smaller than that due to the branching fraction into the reconstructed decay mode, $pK^-\pi^+$. In $\Upsilon (4S)$ decays we measure a total rate of $N_{\Lambda c}^{\Upsilon} = 0.091\pm$0.006(exp.)$\pm$0.024(BF) per $\Upsilon(4S)$ decay, and find a much softer momentum distribution than expected from B decays into a $\Lambda_c^+$ plus an antinucleon and one to three pions.
LAMBDA/C+ differential production rate per hadronic event for the continuum at cm energy 10.54 GeV.
The integrated number of LAMBDA/C+'s per hadronic event for the continuum at cm energy 10.54 GeV.
LAMBDA/C+ differential production rate per UPSILON(4S) decay at cm energy 10.58 GeV.
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THE AVERAGE PHASE IS -130.9 +- 2.7 DEG (NO EXPLICIT MOMENTUM DEPENDENCE). USING ABS(ETA+-) = 2.3*10**-3.
REGENERATION AMPLITUDE ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
CROSS SECTION DIFFERENCES ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
The energy dependence of the modulus and phase of the K L 0 -K S 0 regeneration amplitude on hydrogen in the range of 14–50 GeV has been investigated at the Serpukhov 70 GeV accelerator. It has been established that the modulus of the modified regeneration amplitude decreases with increasing momentum as 2|ƒ 21 0 (p)|/k = (0.84 ± 0.42) · p −0.50±0.15 mb . The amplitude phase is energy-independent and its mean value is ϕ 21 0 = −132° ± 5°. The results obtained are compared with other experiments and with predictions of different theoretical models.
TABLE ALSO CALCULATES FORWARD DIFFERENTIAL CROSS SECTION AND SIG(AK0 P) - SIG(K0 P) TOTAL CROSS SECTION DIFFERENCES.
Cross sections for p ̄ p → n ̄ n at 25 and 35 GeV/ c have been measured. The cross sections decrease with increasing momentum as 1/ P 2 . A narrow peak is observed in the momentum transfer interval 0 ⩽ − t ≲ 0.02 (GeV/ c 2 in the differential cross sections. Neither ϱ nor A 2 exchange contribute to the process in the investigated energy range.
K- CEX MEASURED BY STARS FROM KL AS A CHECK.
No description provided.
No description provided.
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AT PLAB OF 25 GEV, 'REF(8)' HAS 11.0 +- 1.4 MUB WHICH COMBINED WITH THIS MEASUREMENT GIVES 11.6 +- 1.0 MUB.
AT PLAB OF 25 GEV, THE DATA HAVE BEEN COMBINED WITH THOSE OF 'REF(8)'.
No description provided.
Results are presented on the reaction K − p → K̄ o n for momenta above 20 GeV/ c . Events were identified by precise measurement of the opening angle in the decay K o → π + π − without using a magnetic field. The cross-section is described by a power energy dependence.
No description provided.
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