Evidence for a narrow dip structure at 1.9 GeV/c2^2 in 3π+3π−3\pi^+ 3\pi^- diffractive photoproduction

A narrow dip structure has been observed at 1.9 GeV/c$^2$ in a study of diffractive photoproduction of the $~3\pi^+3\pi^-$ final state performed by the Fermilab experiment E687.Comment: The data of Figure 6 can be obtained by downloading the raw data file e687_6pi.txt. v5 (2nov2018): added Fig. 7, the 6 pion energy distribution as requested by a reade

A MEASUREMENT OF GAMMA(DS+->PHI MU+NU) / GAMMA(DS+->PHI-PI+).

Fermilab high-energy photoproduction experiment E687 measures a branching ratio of Gamma (DS+ \u2192 phi mu+nu) /Gamma (DS+ \u2192 phi mu+) = 0.58 \ub1 0.17 (stat) \ub1 0.07 (sys). This branching ratio is combined with theoretical inputs to obtain a new measurement of the DS+ absolute branching ratio of Gamma (DS+ \u2192 phi mu+) / Gamma(DS+ \u2192 all) = 0.031 \ub1 0.009 (stat 0.005 (sys) \ub1 0.004 (theoretical)

Measurment of the masses and widths of L=1 charmed mesons

We report the measurement of masses and widths of the following L=1 charm mesons by the E687 Collaboration at Fermilab: a D(2)*0 state of mass (width) 2453+-3+-2 (25+-10+-5) MeV/c2 decaying to D+pi-, a D(2)*+ state of mass (width) 2453+-3+-2 (23+-9+-5) MeV/c2 decaying to D0pi+, a D(1)0 state of mass (width) 2422+-2+-2 (15+-8+-4) MeV/c2 decaying to D*+pi-, and a D(s1)+ state of mass 2535.0+-0.6+-1.0 MeV/c2 and width <3.2 MeV/c2 at 90% confidence level, decaying to D*+Ks0 and D(*0)K+

Observation of an excited state of the Lambda(c)+ baryon

An observation of an excited Lambda(c)+* baryon decaying to Lambda(c)+pi+pi-, with Lambda(c)+\u2192pK-pi+, is presented. We reconstruct 39.7+-8.7 Lambda(c)+* baryons with a mass of 340.4+-0.6+-0.3 MeV/c2 above the Lambda(c)+ mass. The upper limit on the resonant branching ratio is B(Lambda(c)+*\u2192Sigma(c)pi\ub1)/B(Lambda(c)+*\u2192Lambda(c)+ pi+pi-)<36% at the 90% confidence level

Measurement of the form factors for the decay D(s)+ &#8594; phi mu+ nu

The fermilab high-energy photoproduction experiment E687 provides a sample of approximately 90 events of the decay mode D(s)+\u2192 phi mu+ nu. The ratios of the form factors governing the decay are measured to be Rv=1.8+-0.9+-0.2 and R2= 1.1+-0.8+-0.1, implying a polarization of G1/Gt=1.0+-0.5+-0.1 for the electron decay, consistent with our measurement of the form factor for the decay D+->anti(K0*) mu+ nu

1ST EVIDENCE OF OMEGA-C(0)- > OMEGA- PI+

We report evidence of a narrow resonance at a mass of 2705.9 \ub1 3.3 \ub1 2.0 MeV/c2 in the final state Omega 12\u3c0+ and the charge conjugate. The mass and width support the interpretation of a weakly decaying doubly strange charmed baryon, the Omegac0. Limits on the relative branching ratios for Omegac0\u2192Omega 12K 12\u3c0+\u3c0+ and Omegac0\u2192Omega- pi 12pi+pi+ are also presented

EVIDENCE OF THE CABIBBO-SUPPRESSED DECAY LAMBDA(C)(+)->PK-K+.

We report evidence for the Cabibbo-suppressed decay of the charm baryon \u39bc+ into the final state pK 12K+. The analysis is performed on data collected by high energy photoproduction experiment E687 during the 1990\u20131991 Fermilab fixed target run. The branching ratio of the decay Lambac+ \u2192 pK 12K+ relative to the non-suppressed Lambdac+ \u2192 pK 12pi+ is measured to be BR(pK 12K+/pK 12pi+) = 0.096 \ub1 0.029 \ub1 0.010. The upper limit of the decay into p\uf8 relative to the inclusive pK 12K+ decay is measured to be BR(rho0/pK 12K+ < 58% at the 90% confidence level