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We show that recent measurements of ir~ multiplicity distributions produced in relativistic heavy-ion collisions are in remarkable agreement with the predictions of the collective tube model oRecently two independent experiments have reported 1 * 2 measurements of n" multiplicity distributions produced in relativistic heavy-ion collisions. It was noted 2 * 3 that the observed distributions are significantly different from those expected from an aggregate of individual nucleonnucleon collisions. 3 * 4 In this Letter we show that the collective tube model 5 (CTM) which has been applied with considerable success 6 to predict inelastic particle-nucleus interactions at high energies also reproduces remarkably well the observed 77"" multiplicity distributions in relativistic nucleus-nucleus collisions.Consider a high-energy nucleus-nucleus collisions at impact parameter B (the transverse distance between the nuclear centers) in the centerof-mass system. Let us focus on the collision inside a cylinder of cross section 6 along the incident direction at transverse coordinate b, In this cylinder i x right-moving projectile nucleons collide with i 2 left-moving target nucleons.is the nuclear density function normalized such that J Pjd 3 r = A j0 In the cm. system the colliding tubes are Lorentz contracted into narrow disks. The CTM thus assumes that tube-tube collisions resemble elementary particle-particle collisions. It further assumes that all the simultaneous N(B) tube-tube collisions in the intersection area of the colliding nuclei are independent. [N(B) is equal to the intersection area divided*by a the pp total inelastic cross section. 7 ] For calculating multiplicity distributions the CTM makes use of the observation that the average multiplicity and the multiplicity distribution of negatively charged particles produced in high-energy particle collisions depend only on Q, the available energy for particle production in the cm. system; and hot on the specific nature 8 * 9 (quantum numbers) of the colliding particles [Q is defined by Q = Vs -(m 1 + m 2 ) where Vs is the total cm. energy and m 19 m 2 are the masses of the colliding particles]. Thus the multiplicity distribution of 7i" produced in a highenergy collision of a tube of i x nucleons with a tube of i 2 nucleons is taken from pp collisions at(1) m is the nucleon mass and E is the incident energy per nucleon. The probability P n _ of producing n_ negative pions in an inelastic nucleus-nucleus collision is obtained by averaging P(n_ | £), the probability to produce n-negative pions in a collision with impact parameter B, over all impact parameters, i.e., P n _ = Jdo{B)p{n_ | B)/Jdo(B).(2) da(B) is the contribution to the total inelastic cross section from impact parameter B. It is given by 10Since we assume that all the tube-tube collisions are independent we obtain that P(n.\B)= Z 6(£»,-»-) IT P nk (k),where P nk (k) is the probability for producing n k 7T" in the Mh tube-tube collision in the intersection area. In the incident energy range 1 GeV/c ^^iab ^70 G...

We propose a quark-parton model of a nucleus viewed in a high-momentum frame. We use it to calculate deepinelastic lepton scattering, lepton pair production, W-boson production, particle production at large x and small p,, and cumulative production of particles at backward angles in high-energy hadron-nucleus collisions. Predictions are compared with experimental data. Good agreement between theory and experiment is demonstrated. THE QUARK-PARTON STRUCTUREO F A FAST NUCLEUS Current models of particle production f r o m hadron targets at high energies require a knowledge 1547

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