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# Digital calorimetry for future e$$^+$$e$$^-$$ linear colliders and their impact on the precision measurement of the top Higgs Yukawa coupling

Price, Tony (2013)
Ph.D. thesis, University of Birmingham.

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## Abstract

The International Linear Collider (ILC) is a proposed future e$$^+$$e$$^-$$ linear collider which will make precise measurements of the Standard Model of Particle Physics. Novel detector systems with unprecedented performance are required to allow these measurements. This thesis focuses on the validation of a Digital Electromagnetic Calorimeter (DECAL) which infers the energy of the incident particles by counting the number of pixel fired (particles) in the shower rather than the energy deposited.The TPAC sensor has been developed for use as the active layer of a DECAL and its properties have been studied during beam tests at CERN and DESY. Data from these tests has been used to validate the DECAL concept by showing that pixel multiplicity increases with incident particle energy and material depth as expected for electromagnetic shower development. The radiation hardness of the TPAC sensors was also evaluated with a reduction in the signal to noise ratio of 8 % observed at doses up to 200 krad. The semileptonic decay of e$$^+$$e$$^-$$ $$\rightarrow$$ ttH has been studied at 1 TeV to evaluate the performance of the International Large Detector (ILD) yielding a predicted uncertainty on the measurement of the top Higgs Yukawa coupling of 6.9% with 1000 fb$$^-$$$$^1$$ of data. An investigation into the effect of the inclusion of a DECAL has yielded results consistent with a conventional calorimeter system.

Type of Work: Ph.D. thesis. Watson, Nigel Colleges (2008 onwards) > College of Engineering & Physical Sciences School of Physics and Astronomy QB AstronomyT Technology (General) University of Birmingham 4515
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