A simulated sample of decays of a heavy charged boson of unknown mass is generated…

PHYSICS · Multi-part · Fermi University Physics · Particle Physics & Quantum Fields · Particles, interactions and experiment · Particles, interactions and experiment

Symmetry and Flavour, Ch Four-vectors at work: boosts, invariants and the shape of a final state

Problem

A simulated sample of

100\,000

decays

X\to e\nu

of a heavy charged boson of unknown mass

M_X

is generated with every idealisation of the chapter: zero width, a perfect detector, each decay isotropic in the

X

rest frame, and no transverse motion of

X

. Each

X

is given a different, random motion along the beam. The upper part of the transverse-mass distribution is as follows. Number of events per

m_T

bin, in GeV:

100

–

104

5388

;

104

–

108

6300

;

108

–

112

7688

;

112

–

116

10297

;

116

–

120

25604

;

120

–

124

0

. ((a)) Read an interval for

M_X

from the table alone, and say what feature of the table fixes it. ((b)) For this idealised sample

m_T=M_X|\sin\theta^*|

. Use the count in the

116

–

120\,\mathrm{GeV}

bin to find

M_X

to three significant figures. ((c)) The same decays are regenerated with a much larger spread of longitudinal motion. How does the table change, and why?

Browse the problem library