Measurement of exclusive processes and search for New Physics at the LHC

Presentation of the PhD project of Mohammed El Amine BENAICHOUCHE

With professor Krzysztof PIOTRZKOWSKI

Introduction : Master’s project and CERN summer school.

Photon interactions and exclusive production at the LHC.

Anomalous Quartic Gauge couplings

Novel forward detectors

Work plan

Outline

Introduction : Master’s project

The Quark-Parton Model

• Quark Model

• The Parton Model.

• Gluons and QCD corrections

• The improved Parton Model – Parton evolution equations (DGLAP)

• Experimental determination of the PDFs. – Studied these processes

– Discussed results of HERA experiments (H1 and ZEUS)

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The H1 and ZEUS measurements of the cross section of the NC and CC ep cross sections as a function of Q2

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The Valance and Sea quark, and gluon distributions as obtained from H1 and ZEUS NLO QCD fits to NC , CC and Jet Data at Q2 =

10 GeV2 as a function of x

2010 CERN Summer student project: • Importance of the Vector Boson Fusion

processes (VBF) production of the Higgs boson

• Study of the Triple Gauge Bosons Vertices

(TGCs) in VBF at the LHC

• The studied process was production of Z boson via fusion of two W bosons

with

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• Studying the automatic computations from Lagrangian to Event level.

• Event generator : CalcHEP

• Experimental cuts (on the kinematic variables).

• Studies of the decay of Z boson using CalcHEP-PYTHIA interface and CMSSW.

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Two photon physics at the LHC.

• The LHC as a parasitic photon collider.

• Two Photon interaction : Photon-photon fusion

• Photons are exchanged by both protons and fuse to produce centrally a system X

• In exclusive production both protons survive

importance of new forward detectors.

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Physics potential of two photons interactions:

• Measurements of two-photon production of W boson pairs

unique test of Quartic Gauge Couplings (QGCs)

• Possibility of direct pair production of new massive charged particles, as sleptons or charginos in SUSY

• Exclusive production of the Higgs boson

• QED exclusive production muon pairs for absolute calibration luminosity at the LHC.

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With limited statistics of ~100 events 8

First measurements of exclusive two-photon production at the LHC (2010 data)

2011 summer project at CP3

• Continue measurements of exclusive two-photon interaction at the LHC using 2011 (in collaboration with J. Hollar and N. Schul)

• Simulations : LPAIR event generator.

• Developing new methods for events selection :

- Kinematics selection.

- Efficiency corrections.

- etc.

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Anomalous Quartic Gauge Couplings.

• Fundamental importance of studies of Quartic Gauge Vertices

W + W W + W and Higgs mechanism.

- Quartic Gauge Couplings are not well studied

Any anomaly is a direct sign of New Physics!

• Two photon interactions offer unique opportunity

at the LHC studies of ggWW (and ggZZ) vertex

• Theoretical models need to be implemented to simulate anomalous QGCs (using effective lagrangians)

• New methods and techniques will be developed to complete the study

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Novel forward detectors – GasToF detector

• High Precision Spectrometer (HPS) project in CMS involves installation far from collision point of very-forward detectors close to the beam line of the LHC

• GasToF : Gas Cherenkov counter proposed by a CP3 group for picosecond resolution Time-of-Flight measurements of forward scattered protons

• GasToF : detection of Cerenkov light (after reflection by a mirror) by ultra rapid micro-channel plate photomultipliers (MCP-PMTs)

• Detailed simulations of the detector performance will be confronted with future studies using cosmic rays/at test beams

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Event display using Frog program for a given geometry of GasToF

GasToF concept

Work Plan

• 2011-2012 :

- Measurement of exclusive lepton pair production using 2011 data in CMS.

- Start of a complete study of the ggWW couplings.

- Complete GasToF simulation and test performance of the detector.

• 2013-2014 :

- Publish the first results of the QGCs measurements in CMS.

- Preparations for measurement of the exclusive processes at the energies

of 14 TeV using HPS and its novel detectors .

• 2015 :

- First measurement of photon interaction using new 14 TeV data.

- Finalize analyses and publish PhD thesis.

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