Physics:ND experiment

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Short description: Nuclear physics experiments in Novosibirsk, Russia (1982-1987)

Neutral Detector (ND) is a detector for particle physics experiments created by the team of physicists in the Budker Institute of Nuclear Physics, Novosibirsk, Russia . Experiments with the ND were conducted from 1982 to 1987 at the e+e− storage ring VEPP-2M in the energy range 2E=0.5-1.4 GeV.

Physics

At the beginning of 80s the leading cross sections of the electron-positron annihilation in the final states with charged particles were measured in the energy range 2E=0.5-1.4 GeV. Processes with the neutral particles in the final state were less studied. To investigate the radiative decays of the [math]\displaystyle{ \rho^0 }[/math], [math]\displaystyle{ \omega }[/math], and [math]\displaystyle{ \phi }[/math] mesons and other processes involving photons, [math]\displaystyle{ \pi^0 }[/math], and [math]\displaystyle{ \eta }[/math] mesons the ND [1] was constructed. Its distinguishing features are defined by the specially designed electromagnetic calorimeter based on NaI(Tl) scintillation counters.

List of published analyses [2]

[math]\displaystyle{ e^+e^- \to \rho, \omega, \phi \to \pi^0 \gamma, \eta \gamma }[/math] [3][4]
[math]\displaystyle{ \phi \to \eta^\prime \gamma }[/math] [5]
  • Rare decays of the [math]\displaystyle{ \rho^0 }[/math], [math]\displaystyle{ \omega }[/math], and [math]\displaystyle{ \phi }[/math] mesons
[math]\displaystyle{ \omega, \phi \to \pi^0 e^+e^- }[/math] [6]
[math]\displaystyle{ \phi \to \pi^+ \pi^- }[/math] [7]
  • Search for rare decays
[math]\displaystyle{ \rho \to \pi^+ \pi^- \pi^0 }[/math] [8]
[math]\displaystyle{ \omega, \phi \to \pi^0 \pi^0 \gamma }[/math] [3][5]
[math]\displaystyle{ \phi \to \pi^0 \eta \gamma }[/math] [9]
light scalars [math]\displaystyle{ a_0(980) }[/math] and [math]\displaystyle{ f_0(975) }[/math] in [math]\displaystyle{ \phi }[/math]-meson radiative decays [5]
[math]\displaystyle{ e^+e^- \to \omega \pi^0 }[/math] [10]
[math]\displaystyle{ e^+e^- \to \pi^+ \pi^- \pi^0 ,~~ \pi^+ \pi^- \eta }[/math] [11][12]
[math]\displaystyle{ e^+e^- \to \pi^+ \pi^- \pi^+ \pi^-,~~ \pi^+ \pi^- \pi^0 \pi^0 }[/math] [13]
[math]\displaystyle{ e^+e^- \to \gamma \gamma \gamma \gamma }[/math]
[math]\displaystyle{ e^+e^- \to e^+e^- \gamma \gamma }[/math]
[math]\displaystyle{ e^+e^- \to e^+e^- e^+e^- }[/math]
[math]\displaystyle{ e^+e^- \to e^+e^- \gamma }[/math] (virtual Compton scattering) [16]
  • Analyses of other processes
    • Measurement of the ω-meson parameters [17]
    • Upper limits on electron width of scalar and tensor mesons [math]\displaystyle{ f_0(975) }[/math], [math]\displaystyle{ f_2(1270) }[/math], [math]\displaystyle{ f_0(1300) }[/math], [math]\displaystyle{ a_0(980) }[/math], and [math]\displaystyle{ a_2(1320) }[/math] [18]
    • [math]\displaystyle{ \phi \to \pi^+ \pi^- \pi^0,~~ K^0_S K^0_L }[/math] [19]
    • Search for
      • [math]\displaystyle{ e^+e^- \to \pi^0 \pi^0 \gamma }[/math] [20]
      • [math]\displaystyle{ K^0_S \to \gamma \gamma }[/math] [21]
      • [math]\displaystyle{ e^+e^- \to C(1480) \to \phi \pi^0 }[/math] [22]

Detector

Neutral Detector r-φ view.
Neutral Detector r-θ view; 1-vacuum chamber of the storage ring, 2-cylindrical proportional chambers, 3-plastic scintillation counters, 4-NaI(Tl) counters, 5-flat proportional chambers, 6-iron absorber, 7-anticoincidence counters.

Based on goals of the physics program the ND consist of

Electromagnetic calorimeter

  • 168 rectangular NaI(Tl) scintillation counters
  • total mass of NaI(Tl) is 2.6 t
  • solid angle coverage is 65% of 4π sr
  • minimum thickness is 32 cm or 12 radiation length
  • energy resolution for photons is σ/E = 4% / √E

Charged particle coordinate system

  • 3 layers of coaxial cylindrical 2-d wire proportional chambers in the center of the detector
  • solid angle coverage is 80% of 4π sr
  • angular resolution is 0.5° in the azimuthal and 1.5° in the polar direction
  • surrounded by the 5-mm thick plastic scintillation counter for trigger

Flat (shower) coordinate 2-d wire proportional chambers

  • 2 layers of flat 2-d wire proportional chambers.
  • angular resolution is 2° in the azimuthal and 3.5° in the polar direction for 0.5 GeV photons

Iron absorber & anti-coincidence counters

  • The electromagnetic calorimeter is covered by the 10-cm thick iron absorber and plastic scintillation anti-coincidence counters.

Results

Data collected with the ND experiment corresponds to the integrated luminosity 19 pb−1. Results of the experiments with ND are presented in Ref.,[2] and are included in the PDG Review. [23]

See also

References

  1. ↑ Golubev, V. B. (1984). "The neutral detector at VEPP-2M". Nuclear Instruments and Methods in Physics Research Section A 227 (3): 467–469. doi:10.1016/0168-9002(84)90202-X. Bibcode: 1984NIMPA.227..467G. 
  2. ↑ 2.0 2.1 Dolinsky, S. I. (1991). "Summary of experiments with the neutral detector at the e+e− storage ring VEPP-2M". Physics Reports 202 (3): 99–170. doi:10.1016/0370-1573(91)90127-8. Bibcode: 1991PhR...202...99D. 
  3. ↑ 3.0 3.1 Dolinsky, S. I. (1984). "Radiative decays of ρ and ω mesons". Zeitschrift für Physik C 42 (4): 511–518. doi:10.1007/BF01557655. 
  4. ↑ Druzhinin, V. P. (1984). "Measurement of Φ-meson radiative decays at the storage ring VEPP-2M with the neutral detector". Physics Letters B 144 (1–2): 136–140. doi:10.1016/0370-2693(84)90192-8. Bibcode: 1984PhLB..144..136D. 
  5. ↑ 5.0 5.1 5.2 Druzhinin, V. P. (1987). "Search for rare radiative decays of Φ-meson at VEPP-2M". Zeitschrift für Physik C 37 (1): 1–5. doi:10.1007/BF01442062. Bibcode: 1987ZPhyC..37....1D. 
  6. ↑ S.I. Dolinsky et al., Sov. J. Nucl. Phys. 48 (1988) 277.
  7. ↑ V. B. Golubev et al., Sov. J. Nucl. Phys. 44 (1986) 409.
  8. ↑ V. B. Vasserman et al., Sov. J. Mod. Phys. 48 (1988) 480.
  9. ↑ V. M. Aulchcnko et al., Preprini INP 87-90 (Novosibirsk, 1987).
  10. ↑ Dolinsky, S. I. (1986). "The reaction e+e− → ωπ0 in the cm energy range from 1.0 to 1.4 GeV". Phys. Lett. B 174 (4): 453–457. doi:10.1016/0370-2693(86)91036-1. Bibcode: 1986PhLB..174..453D. 
  11. ↑ A. D. Bukin et al., Sov. J. Nucl. Phys. 50 (1989) 621.
  12. ↑ Druzhinin, V. P. (1986). "Investigation of the reaction e+e− → ηπ+π− in the energy range up to 1.4 GeV". Phys. Lett. B 174 (1): 115–117. doi:10.1016/0370-2693(86)91140-8. Bibcode: 1986PhLB..174..115D. 
  13. ↑ V. M. Aulchenko et al., Preprint INP 86-106 (Novosibirsk, 1987).
  14. ↑ V. P. Druzhinin et al., Preprint INP 85-98 (Novosibirsk, 1985).
  15. ↑ V. M. Aulchcnko et al., Preprint INP 86-173 (Novosibirsk, 1986).
  16. ↑ V. B. Golubev et al., Sov. J. Nucl. Phys. 41(1985) 752.
  17. ↑ Aulchenko, V. M. (1987). "The width of the ω-meson". Phys. Lett. B 186 (3–4): 432–434. doi:10.1016/0370-2693(87)90322-4. Bibcode: 1987PhLB..186..432A. 
  18. ↑ P. V. Vorobyov et al., Sov. J. Nucl. Phys. 48 (1988) 436.
  19. ↑ V. P. Druzhinin et al., Preprint INP 85-97 (Novosibirsk, 1985).
  20. ↑ V. B. Golubev et al., Sov. J. Nucl. Phys. 45 (1987) 622.
  21. ↑ I. B. Vasserman et al., JETP Lett. 43(1986) 588.
  22. ↑ V. M. Aulchenkoet al., JETP Lett. 45 (1987) 145.
  23. ↑ The Review of Particle Physics, K. Nakamura et al. (Particle Data Group), J. Phys. G 37, 075021 (2010)

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