Svenska:

Den här webbplatsen kan endast nås som arkivreferens. De officiella webbsidorna för avdelningen för partikelfysik finns på http://particlephysics.physics.lu.se

Sidan nedan slutar uppdateras fr.o.m. 2020-09-22 och uppfyller endast delvis tillgänglighetsdirektivet. Se tillgänglighetsredogörelsen

English:

The webpage you reached is made available for archiving purposes only. The official division of particle physics webpages can be found at http://particlephysics.physics.lu.se

The page below is not updated any longer since September 22, 2020 and does not conform completely to the accessibility regulation. See the accessibility statement

STIC single arm triggers

The STIC single arm triggered events can be used to measure the rate of off-energy electrons in STIC [5]. This trigger requires a shower with an energy greater than $\sim$ 0.25 ^. E_beam in one of the two calorimeters. The trigger is dynamically downscaled to a constant trigger rate, and this has to be taken into account in the estimation of the rate. Figure 12 shows the rate of off-energy electrons in STIC normalized to luminosity. In 1997 the typical rate of off-energy electrons in STIC was 8 ^. 10⁶ per pb ^-1. The rate has decreased each year and it is now < 2 ^. 10⁶ per pb ^-1.

Figure: 12 Left: The number of off-energy electrons in STIC per pb^-1. Only the first 400-500 high energy fills during each year are shown. Right: The energy and theta-phi distributions of events recorded by the STIC single arm trigger. Data from fill 5941 were used.

The energy and angular distributions of the off-energy electrons in STIC are shown in Figure 12 for 1999B data from fill 5941. Most of the background has a large energy and is in the horizontal plane, which results in peaks in the theta-phi distribution. This horizontal background component can, however, be removed by a cut on the polar angle since it does not extend much above 3^o.