Charged Projectile Fragments Research Articles

Anomalons at intermediate relativistic energies

The mean-free path of anomalons at intermediate relativistic incident energies of 2-5 GeV/n and the doubly charged projectile fragments of Z=2, 6 and 8 in relativistic collisions can be explained as Lambda particles bound to the He, C and O nuclei using conventional hypernuclear interactions. Analysis shows a dependence of the anomalon effect on the PF charge Z, and therefore the anomalons are not general phenomena. The projectile incident energy changes the reaction dynamics, so that formation of a hypernucleus is possible only under certain collision scenarios.

Are Z = 2 anomalons fractionally charged projectile nuclei?

This paper reports a preliminary study on the measurement of the charge of projectile fragments having [Formula: see text] in extreme peripheral interactions of C12 with emulsions at 4.5 GeV ∙ c−1 ∙ n−1. This study was done to determine if Z = 2 anomalons are third integral fractionally charged nuclei. This method of charge measurement is based on the determination of lacunarity and estimates the charge of relativistic projectile fragments (PFs) with a standard deviation of [Formula: see text]. No evidence for the existence of fractionally charged PF has been found, and possible implications are discussed.

Behavior of projectile fragments of 1.88 GeV/nucleon 56Fe.

The projectile fragments from 1.88 GeV/nucleon $^{56}\mathrm{Fe}$ collisions with light (CR-39 plastic) and heavy (Cu) nuclei were analyzed in a CR-39 chamber with spacers. No decay of projectile fragments in space was observed. No anomaly was clearly observed for interactions, of projectile fragments in the CR-39 chamber. The overall normalized cross sections ${\ensuremath{\sigma}}^{\mathrm{*}}$ was 1.13\ifmmode\pm\else\textpm\fi{}0.07\ifmmode\pm\else\textpm\fi{}0.06 in CR-39 for projectile fragments emitted by collisions of $^{56}\mathrm{Fe}$ with Cu and CR-39 targets, though ${\ensuremath{\sigma}}_{\mathrm{CR}\mathrm{?}(\mathrm{h}\mathrm{y}39{}^{\mathrm{*}}(6\mathrm{\ensuremath{\le}}\mathrm{z}\mathrm{\ensuremath{\le}}11}$) of 1.42\ifmmode\pm\else\textpm\fi{}0.25\ifmmode\pm\else\textpm\fi{}0.13 was obtained for projectile fragments of lower charge (6\ensuremath{\le}z\ensuremath{\le}11) from light target nuclei (CR-39).

Search for fractionally charged nuclei in high-energy heavy-ion collisions

An experiment was performed to search for fractionally charged nuclei with charge $Z$, $14<~Z<~18$, produced as projectile fragments of 1.8-GeV/nucleon $^{40}\mathrm{Ar}$. Analysis of 1.75 \ifmmode\times\else\texttimes\fi{} ${10}^{5}$ projectile fragments yielded no fragments with charges differing from integer values by more than $\ifmmode\pm\else\textpm\fi{}\frac{1}{3}e$. This experiment places limits (90% C.L.) on the relative abundance of fractionally charged projectile fragments with residual charge $+\frac{1}{3}e(\ensuremath{-}\frac{1}{3}e)$ of less than 1.8 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$ (2.3 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$.

Search for relativistic projectile fragments with charges of [formula omitted] and [formula omitted

We present the results of 1179 precise charge measurements carried out on 1 ⩽ Z ⩽ 3 projectile fragment nuclei from relativistic nucleus-nucleus collisions in nuclear emulsion. We find no evidence for the existence of third-integral fractionally charged projectile fragments, particularly for those with charges 5 3 and 7 3 .

Search for Nonintegrally Charged Projectile Fragments in Relativistic Nucleus-Nucleus Collisions

Using dioctyl-phthalate-doped CR-39 plastic track detectors with charge resolution ${\ensuremath{\sigma}}_{Z}\ensuremath{\approx}0.06e$, the authors have made the first dynamic search for fractionally charged particles bound to nuclei. They find, from charge measurements in the first \ensuremath{\sim} 2 cm after production, that no more than 3 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}3}$ (95% confidence level) of the projectile fragments of 1.85-GeV/u $^{40}\mathrm{Ar}$ interactions with $10l~Zl18$ have charges differing from an integer by as much as $0.3e$. This rules out explanations of anomalons based on models in which the anomalons have nonintegral charge in such charge range.

Production cross sections of multiply charged fragments in heavy ion interactions at 150–200 MeV/nucleon

A total of 1720 16O-emulsion nucleus interactions at 150–200 MeV/nucleon have been investigated. Production cross sections of multiply charged projectile fragments are given. It is found that the cross section for the production of N, C, B and Be projectile fragments in 16O-nucleus interactions is similar at 0.2 and 2 GeV/nucleon. The fragmentation cross sections for Li and He are larger at 0.2 than at 2 GeV/nucleon.