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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 $e^{+}e^{-}$ annihilation process. A high intensity positron beam, with energy just above the 47.3 GeV threshold for muon pair production through $e^{+}e^{-} \rightarrow \mu ^{+} \mu ^{-}$ 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 $E_{3}$ in the central LG unit. Fig. 1 shows the average electron (muon) released energy $\left \langle E_{3} \right \rangle$ in the central LG unit in blu (green), as a function of the $x$ position measured by the tracker.

Figure 1: 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.

HOrizontal Smart Absorber efficiency

he efficiency of each HORSA active layer $j = 5,6,7,8$ (numbers refer to Fig. 2) 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 Wiki Lab2Go. Il testo, la figura e la tabella riportati sono stati presi dall'articolo scientifico arxiv:2105.12624

Commento di Fausto C.

La figura andava centrata, inoltre qualche imprecisione (es. mancano dei pedici, come $N_4$, $E_0$) ma va bene. Ti do 1h di lavoro a casa

Ps. Inoltre, come scritto nel testo, la soglia di produzione della coppia di muoni è 43.7GeV e non 47.3GeV :-D

playground/simone_r_galilei2021.txt · Ultima modifica: 2021/12/10 08:18 da fausto.casaburo