Results of a search for thehc(P11)state of charmonium in theη

Feasibility study for the measurement of πN transition distribution amplitudes at P¯Singh1, Erni2, Krusche3 et al. 2017Phys. Rev. DSelf Cite411250View full textAdd to dashboardCite

“…Figure 5 shows the Δ 2 T dependence of the cross section for the three collision energies which are used for the studies addressed here, each of them limited to its validity range. It is possible to compare this prediction to the E835 measurement of thepp → J=ψπ 0 → e þ e − π 0 cross section [17][18][19], taken at an incidentp momentum of 5.5 GeV=c that corresponds to s ¼ 12.3 GeV 2 or ffiffi ffi s p ¼ 3.5 GeV. This value of ffiffi ffi s p is 25 MeV below the threshold for the production of the h c resonance.…”

“…energy s: 12.3 GeV 2 , 16.9 GeV 2 , and 24.3 GeV 2 . The first value is chosen to coincide with existing data from E835 forpp → J=ψπ 0 [17][18][19]. The remaining two values are chosen at the incidentp momenta of 8 GeV=c and 12 GeV=c, respectively, to explore the kinematic zone between the first point and the maximum availablep momentum at FAIR of 15 GeV=c.…”

“…The simultaneous measurement of both resonant and nonresonant channels provides constraints to the πN TDAs in different kinematic ranges and allows one to test the universality of πN TDAs. While the nonresonantpp → γ Ã π 0 → e þ e − π 0 has never been measured, some scarce data exist forpp → J=ψπ 0 → e þ e − π 0 [17][18][19], which can be used to constrain the predictions. Production of a J=ψ with an associated π 0 inpp collisions has indeed been investigated in the past by the E760 experiment at FNAL, since it constitutes a background in the search for charmonium states via their decay into J=ψπ 0 .…”

Search for hc→π+π−J/ψ<

“…Evidence for the h c state was reported in pp → h c → γη c by E835 [6] at Fermilab. The first observation of the h c was reported by CLEO in a study of the cascade decay ψð3686Þ → π 0 h c ; h c → γη c [7].…”

On the mass and decay constant of the P-wave ground and radially excited h c and h b axial-vector mesons

“…The P-wave state h c (1P ) has been confirmed frequently since its first detection in the pp collisions by the R704 collaboration [25]. The FNAL E760 experiment looked for the h c in the reaction pp → h c → π 0 J/ψ → e + e − and announced a statistically significant enhancement with M hc = 3526.2 ± 0.2 ± 0.2MeV and Γ hc ≤ 1.1MeV [26]. The best clue for the h c (1P ) came out from the CLEO collaboration when looking for the isospin violating transition e + e − → Υ(2S) → h c π 0 [27].…”