Bose-Einstein correlations in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mi mathvariant="normal">−</mi></mrow></msup></mrow></math> annihilations in the Υ region

We have used the CLEO detector to study Bose-Einstein (BE) correlations among charged pions produced in the hadronic decays of the Υ(1S) and in continuum $e^{+}$ $e^{-}$ annihilations around √s =10.5 GeV. We discuss different parametrizations of the effect, and find indications that the production of long-lived particles in these events can account for the observed reduction of the strength of the effect. We determined source dimensions of quark and gluon jets. From the standpoint of BE correlations, we see no difference between the hadronization of quarks and gluons.

References (27)

G. Goldhaber, S. Goldhaber, W. Lee and A. Pais, Phys. Rev. Lett. 3, 181 (1959); Phys. Rev. 120, 300 (1960). For a recent review and further references, see also G. Goldhaber, Lawrence Berkeley Laboratory Report No. LBL-19417, 1985 (unpublished).
T. Åkesson et al., Phys. Lett. 129B, 269 (1983).
M. Deutchmann et al., Nucl. Phys. B204, 333 (1982).
C. Ezell et al., Phys. Rev. Lett. 38, 873 (1977).
S. Barshay, Phys. Lett. 130B, 220 (1983).
G. Goldhaber, in Proceedings of the International Conference on High Energy Physics, Lisbon, 1981, edited by J. Dias de Deus and J. Soffer (European Physical Society, Erice, 1982).
W. Koch, in Multiparticle Dynamics, 1982, proceedings of the XIIIth International Symposium, Volendam, The Netherlands, edited by E. W. Kittel, W. Metzger, and A. Stergiou (World Scientific, Singapore, 1983).
R. R. Saurwein, Bull. Am. Phys. Soc. 29, 740 (1984).
H. Aihara et al., Phys. Rev. D 31, 996 (1985).
F. B. Yano and S. E. Koonin, Phys. Lett. 78B, 556 (1978).
S. Y. Fung et al., Phys. Rev. Lett. 41, 1592 (1978).
W. A. Zajc et al., Phys Rev. C 29, 2173 (1984).
J. J. Lu et al., Phys. Rev. Lett. 46, 898 (1981).
D. Beavis et al., Phys. Rev. C 27, 910 (1983).
G. Cocconi, Phys. Lett. 49B, 459 (1974).
G. I. Kopylov, Phys. Lett. 50B, 472 (1974).
G. I. Kopylov and M. I. Podgoretsky, Yad. Fiz. 18, 656 (1973) [Sov. J. Nucl. Phys. 18, 336 (1974)].
D. Andrews et al., Nucl. Instrum. Methods 211, 47 (1983).
S. Behrends et al., Phys. Rev. D 31, 2161 (1985).
D. Besson et al., Phys. Rev. Lett. 54, 381 (1985).
M. Gyulassi, S. K. Kauffmann and L. W. Wilson, Phys. Rev. 20C, 2267 (1979).
G. N. Fowler and R. M. Weiner, Phys. Lett. 70B, 201 (1977).
S. Brandt and H. D. Dahmen, Z. Phys. C 1, 61 (1979).
Strictly speaking, we cannot say that these pions do not interfere. However, the enhancement in plots of $q_{T}$ due to interference of pions from a resonance that has traveled n fm before decaying has a typical width of 0.16/n GeV, which is too narrow for our observation for n >>1 fm [Eqs. (26) and (28)].
T. Sjöstrand, Comput. Phys. Commun. 27, 243 (1982).
P. Grassberger, Nucl. Phys. B120, 231 (1977).
The assertion that the asymptotic behavior in Fig. 9(a) is a simple linear function of $q_{T}$ is based solely on the fact that it seems a reasonable thing to do from looking at the figure. There is no theoretical argument. This gives rise to the term (1+ ${mq}_{T}$ ) in (20). Several authors display their data as a function of $q_{T}^{2}$ rather than $q_{T}$ . For them, the natural step to take, upon observing that their ratios do not approach a constant for large $q_{T}$ , is to introduce a factor (1+ ${mq}_{T}^{2}$ ) in their fits (see Refs. 7, 3, 6, and 26). Choosing linearity in $q_{T}$ or $q_{T}^{2}$ can affect the values of alpha and beta. For example, allowing for a quadratic term in the fit of Fig. 9(a) can lead to changes in alpha and beta of up to 20%.

[c1] G. Goldhaber, S. Goldhaber, W. Lee and A. Pais, Phys. Rev. Lett. 3, 181 (1959); Phys. Rev. 120, 300 (1960). For a recent review and further references, see also G. Goldhaber, Lawrence Berkeley Laboratory Report No. LBL-19417, 1985 (unpublished).

[c2] T. Åkesson et al., Phys. Lett. 129B, 269 (1983).

[c3] M. Deutchmann et al., Nucl. Phys. B204, 333 (1982).

[c4] C. Ezell et al., Phys. Rev. Lett. 38, 873 (1977).

[c5] S. Barshay, Phys. Lett. 130B, 220 (1983).

[c6] G. Goldhaber, in Proceedings of the International Conference on High Energy Physics, Lisbon, 1981, edited by J. Dias de Deus and J. Soffer (European Physical Society, Erice, 1982).

[c7] W. Koch, in Multiparticle Dynamics, 1982, proceedings of the XIIIth International Symposium, Volendam, The Netherlands, edited by E. W. Kittel, W. Metzger, and A. Stergiou (World Scientific, Singapore, 1983).

[c8] R. R. Saurwein, Bull. Am. Phys. Soc. 29, 740 (1984).

[c9] H. Aihara et al., Phys. Rev. D 31, 996 (1985).

[c10] F. B. Yano and S. E. Koonin, Phys. Lett. 78B, 556 (1978).

[c11] S. Y. Fung et al., Phys. Rev. Lett. 41, 1592 (1978).

[c12] W. A. Zajc et al., Phys Rev. C 29, 2173 (1984).

[c13] J. J. Lu et al., Phys. Rev. Lett. 46, 898 (1981).

[c14] D. Beavis et al., Phys. Rev. C 27, 910 (1983).

[c15] G. Cocconi, Phys. Lett. 49B, 459 (1974).

[c16] G. I. Kopylov, Phys. Lett. 50B, 472 (1974).

[c17] G. I. Kopylov and M. I. Podgoretsky, Yad. Fiz. 18, 656 (1973) [Sov. J. Nucl. Phys. 18, 336 (1974)].

[c18] D. Andrews et al., Nucl. Instrum. Methods 211, 47 (1983).

[c19] S. Behrends et al., Phys. Rev. D 31, 2161 (1985).

[c20] D. Besson et al., Phys. Rev. Lett. 54, 381 (1985).

[c21] M. Gyulassi, S. K. Kauffmann and L. W. Wilson, Phys. Rev. 20C, 2267 (1979).

[c22] G. N. Fowler and R. M. Weiner, Phys. Lett. 70B, 201 (1977).

[c23] S. Brandt and H. D. Dahmen, Z. Phys. C 1, 61 (1979).

[c24] Strictly speaking, we cannot say that these pions do not interfere. However, the enhancement in plots of $q_{T}$ due to interference of pions from a resonance that has traveled n fm before decaying has a typical width of 0.16/n GeV, which is too narrow for our observation for n >>1 fm [Eqs. (26) and (28)].

[c25] T. Sjöstrand, Comput. Phys. Commun. 27, 243 (1982).

[c26] P. Grassberger, Nucl. Phys. B120, 231 (1977).

[c27] The assertion that the asymptotic behavior in Fig. 9(a) is a simple linear function of $q_{T}$ is based solely on the fact that it seems a reasonable thing to do from looking at the figure. There is no theoretical argument. This gives rise to the term (1+ ${mq}_{T}$ ) in (20). Several authors display their data as a function of $q_{T}^{2}$ rather than $q_{T}$ . For them, the natural step to take, upon observing that their ratios do not approach a constant for large $q_{T}$ , is to introduce a factor (1+ ${mq}_{T}^{2}$ ) in their fits (see Refs. 7, 3, 6, and 26). Choosing linearity in $q_{T}$ or $q_{T}^{2}$ can affect the values of alpha and beta. For example, allowing for a quadratic term in the fit of Fig. 9(a) can lead to changes in alpha and beta of up to 20%.

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Bose-Einstein correlations in $e^{+}$ $e^{-}$ annihilations in the Υ region

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Bose-Einstein correlations in e+e− annihilations in the Υ region

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Bose-Einstein correlations in $e^{+}$ $e^{-}$ annihilations in the Υ region