Two Photon Trigger Analysis

A study of Two Photon Trigger Efficiency is performed on Bhabha events selected according to criteria of selection A of Method 2.
A description of the Method 2 can be found in the DELPHI NOTE 96-22 PHYS 597

Here below are the PRELIMINARY results.

• 1997:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1997 E=130-136 GeV:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1996 P2:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1996 P1:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1995 P3:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1995:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1994:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1993:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

Results for FORWARD - BACKWARD trigger in the acceptance 25° < theta(e-) < 32.4°, 147.6° < theta(e+) < 155°, and Acollinearity(e+,e-) < 7.4°.

• 1997:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

Here below the trigger efficiency has been estimated comparing the number of HPCLO_MJ2 triggers with SINGLE PHOTON BARREL (SPB) triggers.
Defining e1,2=trigger efficiency for detecting one photon in one hemisphere, and supposing the energies well above the thresholds, the efficiency of HPCLO_MJ2 is eLO=e1·e2 and the one of SPB is eHI=e1+e2-e1·e2.
In the ipothesis e1=e2, e1 and eHI can be measured from the ratio R=#(HPCLO_MJ2*SPB)/#SPB using the relations e1=2·R/(1+R) and eHI=4·R/(1+R)².

• 1997:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1997 E=130-136 GeV:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1996 P2:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1996 P1:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1995 P3:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1995:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1994:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1993:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

Here below are the same quantities, but measured on a sample of e+e- --> gamma gamma (gamma) real data selected in the same acceptance region 42° < theta(g1,g2) < 138° and Acollinearity(g1,g2) < 30°.

• 1997:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1997 E=130-136 GeV:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1996 P2:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1996 P1:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1995 P3:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1995:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1994:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

• 1993:

  • R,e1,eHI vs Time
  • Time integrated R,e1,eHI vs cos(theta)

Single Photon Trigger Analysis

A study of Single Photon Trigger Efficiency is performed on events selected if having a single electromagnetic cluster respectively in BARREL, ENDCAP C and ENDCAP A, with energy:

E > 20 GeV

• 1997:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1997 E=130-136 GeV:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1996 P2:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1996 P1:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1995 P3:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1995:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1994:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

• 1993:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)

E > 2 GeV

• 1997:

  • Trigger Efficiency vs Time
  • Time integrated Trigger Efficiency vs cos(theta)
  • FEMC Trigger Efficiency vs Energy