ISSN:
1434-6052
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract. The DIS diffractive cross section, $d\sigma^{di\!f\!f}_{\gamma^* p \to XN}/dM_X$ , has been measured in the mass range $M_X 〈 15$ GeV for $\gamma^*p$ c.m. energies $60 〈 W 〈 200$ GeV and photon virtualities $Q^2 = 7$ to 140 GeV $^2$ . For fixed $Q^2$ and $M_X$ , the diffractive cross section rises rapidly with $W$ , $d\sigma^{di\!f\!f}_{\gamma^*p \to XN}(M_X,W,Q^2)/dM_X \propto W^{a^{diff}}$ with $a^{diff} = 0.507 \pm 0.034 (stat)^{+0.155}_{-0.046}(syst)$ corresponding to a t-averaged pomeron trajectory of $\overline{ \alpha_{_{{\mathbb P}}} } = 1.127 \pm 0.009 (stat)^{+0.039}_{-0.012} (syst)$ which is larger than $\overline{ \alpha_{_{{\mathbb P}}} }$ observed in hadron-hadron scattering. The W dependence of the diffractive cross section is found to be the same as that of the total cross section for scattering of virtual photons on protons. The data are consistent with the assumption that the diffractive structure function $F^{D(3)}_2$ factorizes according to $x_{_{{\mathbb P}}} F^{D(3)}_2 (x_{_{{\mathbb P}}},\beta,Q^2) = (x_0/ x_{_{{\mathbb P}}})^n F^{D(2)}_2(\beta,Q^2)$ . They are also consistent with QCD based models which incorporate factorization breaking. The rise of $x_{_{{\mathbb P}}} F^{D(3)}_2$ with decreasing $x_{_{{\mathbb P}}}$ and the weak dependence of $F^{D(2)}_2$ on $Q^2$ suggest a substantial contribution from partonic interactions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100500050315
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