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Muon detection in electron-positron annihilation for muon collider studies

Introduction

The LEMMA project aims to study the possibility of producing muons from the e+ e− annihilation process. A high intensity positron beam, with energy just above the 43.7 GeV threshold for muon pair production through the e+ e− → µ+ µ− process, impinging on a low Z fixed target could produce muons with naturally small divergence, resulting in a low transverse emittance.

Tracker-absorbers correlation

As a first step, this analysis studied the relation between the particle's x position measured by the tracker positioned before the first scintillator of the negative arm and the energy released E3 in the central LG unit. Fig. 1 shows the average electron (muon) released energy ⟨E3⟩ in the central LG unit in blu (green), as a function of the x position measured by the tracker:

Figure 1: Figure 3: Average energy released $\left\langle E_{3}\right\rangle$ by 22 GeV electrons (blue, on the top) and muons (green, on the bottom) in the central LG unit as a function of the local x position measured by the tracker. Vertical solid lines are used to mark the region 6 cm < x < 9 cm, considered for further analysis. caption

HOrizontal Smart Absorber efficiency

The efficiency of each HORSA active layer has been studied using a muon beam with energy E0. The efficiency of each HORSA active layer j = 5, 6, 7, 8 is defined as:

$$\varepsilon_{j}=\frac{N_{4}}{N_{3}\left(j\right)}$$

where N4 represents the number of events with signals in time coincidence in all four layers while N3 (j) represents the number of events with signals in time coincidence in all the layers but the j one. The overall efficiency of the HORSA absorber is defined as:

$$\varepsilon_{\text{HORSA}}=\prod_{j=5}^{8}\varepsilon_{j}$$

Results obtained from the run with a muon beam of energy E0 and no target in place are given in Tab. 1, together with the corresponding statistical uncertainties evaluated assuming binomial statistics.

$j$ $\varepsilon_{j}\left(\%\right)$ $\varepsilon_{HORSA}\left(\%\right)$
5$ 97.04\pm0.56$$84.2\pm1.4$
6$ 95.50\pm0.66$
7$ 93.26\pm0.98$
8$ 97.44\pm0.79$

Table 1: Efficiencies to detect a 22 GeV muon in each of the fused silica HORSA layers together with the overall HORSA efficiency, as defined in Equations 1 and 2 respectively.

Nota

Questa è una pagina di prova di utilizzo di Wiki Lab2Go. Il testo, la figura e la tabella riportati sono stati presi dall'articolo scientifico arxiv:2105.12624

Commento di Fausto C.

Qualche imprecisione (es. non hnai usato latex nelle formule in linea col testo), ma va bene. Ti do 1h di lavoro a casa

playground/matteo_z_galilei2021.txt · Ultima modifica: 2021/12/09 07:17 da fausto.casaburo