Probing Hadroproduction Processes with Charm Meson Pairs from 500 GeV $$\pi^-$$ Interactions
- UC, Santa Cruz
We have fully reconstructed approximately 800 $$D\bar{D}$$ events from data gathered by the fixed target hadroproduction experiment E791 at Fermi National Accelerator Laboratory | the largest sample of charm-pair events collected to date. We find slight correlations between the D and $$\bar{D}$$ longitudinal momenta and between the amplitudes of the transverse momenta. As with previous charm-pair experiments, we find significant correlations between the directions of the D and $$\bar{D}$$ mesons in the plane transverse to the beam axis. We also find that the difference between the D and $$\bar{D}$$ azimuthal angles, $$\Delta \phi$$, is strongly correlated to the scalar sum of the squares of the transverse momenta, $$\Sigma p^2_t$$ . The larger $$\Sigma p^2_t$$ is, the more peaked at $$180^{\circ}$$ the $$\Delta \phi$$ distribution is. In a leading-order perturbative QCD calculation, the charm and anti-charm particle are produced back-to-back in the plane transverse to the beam axis. Hence, at leading-order, the $$\Delta \phi$$ distribution is a delta function at $$\Delta \phi = 180^{\circ}$$. As the energy scale of the partonic hard-scattering that produces the charm pair increases (i.e., as $$\Sigma p^2_t$$ increases), we expect higher-order corrections to play a smaller role and, consequently, we expect the leading-order prediction to become more accurate....
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1421751
- Report Number(s):
- FERMILAB-THESIS-1996-16; 433750
- Country of Publication:
- United States
- Language:
- English
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