master defense 2015

Search for Supersymmetry in the

Higgs Sector Master’s thesis

Mohammed El Amine BENAICHOUCHE

Under the supervision of Prof. Ulrich GOERLACH

Outline Goal: Generate events of p-p collision with neutral Higgs bosons in

Supersymmetry using the event generator MadGraph5

1. Introduction

2. Standard Model Higgs Boson production via gluon-gluon fusion

3. Neutral Higgs Bosons in the NMSSM (Next-to-the-Minimal-

Supersymmetric-Standard-Model)

4. Conclusions and perspectives

Search for SUSY in the Higgs sector 2

1. Introduction: The Standard Model and Supersymmetry

Relativistic Quantum Mechanics

Quantum Field Theory

Gauge Theories

The Standard Model

The Higgs mechanism

The discovery of the Higgs Boson (2012) at CERN

Shortcomings of the Standard Model

What is Supersymmetry?


1. Introduction:

The Higgs sector in the SM and Supersymmetric Models

The Higgs Mechanism in the SM

The Higgs Mechanism version in Supersymmetry

The Higgs sector in the MSSM: h, H, A, H±

The MSSM superpotential

The µ-problem in the MSSM and the dynamical solution in the NMSSM

How do we obtain NMSSM from MSSM

The Higgs sector in the NMSSM


1. Introduction:

The Higgs sector in the SM and Supersymmetric Models

The Higgs Mechanism in the SM

The Higgs Mechanism version in Supersymmetry

The Higgs sector in the MSSM: h, H, A, H±

The MSSM superpotential

The µ-problem in the MSSM and the dynamical solution in the NMSSM

How do we obtain NMSSM from MSSM

The Higgs sector in the NMSSM: h, Hs, H, As, A, H±




MadGraph5_aMC@NLO performs computations at tree-level and

one loop QCD amplitudes for arbitrary processes

Such computations are then used to predict physical observables

like the x-sections.

Delphes Detector events

Pythia Shower/Hadronize events

MadGraph Description of proton using pdf

Matrix-element

Parton level


The importance of Gluon-Gluon fusion process of production of

the Higgs boson via Top-Quark loop at the LHC



The Higgs effective field theory(HEFT)

Using the HEFT model, I got for the

125.09 GeV SM Higgs boson effective

coupling to the Gluon 𝑔ℎ = 5.11 × 10−5

The graph illustrates the effective

couplings of the Gluon with the

Higgs Boson in function of the Higgs

mass



1) Study of 𝑔𝑙𝑢𝑜𝑛 − 𝑔𝑙𝑢𝑜𝑛 𝑓𝑢𝑠𝑖𝑜𝑛 → 𝐻𝑖𝑔𝑔𝑠 𝐵𝑜𝑠𝑜𝑛 → 𝑑𝑖𝑝ℎ𝑜𝑡𝑜𝑛 (a1, a2 are two photons)

(Delphes CMS level) ; at 13 TeV

2) Study of 𝑔𝑙𝑢𝑜𝑛 − 𝑔𝑙𝑢𝑜𝑛 𝑓𝑢𝑠𝑖𝑜𝑛 → 𝐻𝑖𝑔𝑔𝑠 𝐵𝑜𝑠𝑜𝑛 → 𝑍 𝑍∗ → 𝑚𝑢 + 𝑚𝑢 − 𝑚𝑢 + 𝑚𝑢 − using MadAnalysis5 (Delphes CMS level) ; at 13 TeV


← 𝑍 𝑚𝑎𝑠𝑠 − 𝑝𝑒𝑎𝑘

Z−𝑝𝑒𝑎𝑘 →

𝐻 − 𝑝𝑒𝑎𝑘 →

𝑍 𝑍 − 𝑝𝑒𝑎𝑘 →

𝑀 𝛾 𝛾 (𝐺𝑒𝑉

𝑐2 ) 𝑀 𝛾 𝛾 (

𝐺𝑒𝑉

𝑐2 )

𝑃𝑡 > 35𝐺𝑒𝑉; 𝜂 < 2.7

𝐻 → 𝑍 𝑍∗ → 𝑚𝑢 + 𝑚𝑢 − 𝑚𝑢 + 𝑚𝑢 −

𝑃 𝑃 → 𝑚𝑢 + 𝑚𝑢 − 𝑚𝑢 + 𝑚𝑢 −



They scanned all the parameters space of NMSSM relevant for the Higgs sector in the 13 TeV run2 of the LHC taking into account experimental limits

from LHC run1, Tevatron and LEP

One of the 5 NMSSM Neutral Higgs bosons has always to be SM-Like

They presented a series of benchmark scenarios for run2 of the LHC at 13 TeV compatible with the experimental constraints




We have chosen the scenario B.1 to start with because it has low

masses and interesting topologies of decays

Indirect production channels:

Higgs-to-Higgs decays and Higgs-to-Higgs + Gauge-boson decays




I have used two fortran codes to calculate the Higgs masses:

NMSSMTools and NMSSMCALC which calculate the Higgs

masses, couplings and decay widths in the NMSSM

NMSSMTools performs computation of the spectrum includes

leading two loop terms, electroweak corrections and propagator

corrections whilst NMSSMCALC performs only a computation of

the full one loop corrections.


PDG

code

Particle Mass (GeV)

NMSSMTools

Mass (GeV)

NMSSMCALC

25 Lightest neutral scalar h 125.37 124.42

35 Second neutral scalar Hs 181.72 188.40

45 Third neutral scalar H 322.64 361.11

36 Lightest pseudoscalar As 72.40 75.04

46 Second pseudoscalar A 311.65 344.32



Using Translator2.2 ( written by B. Fuks) :

To get the Higgs bosons events generated one needs to do the proper calculations of the Gluon-Higgs couplings for all 5 Higgses

We need to make the HEFT working in MG5 for the NMSSM

I modified the C++ code translator 2.2 to translate the reduced couplings from NMSSMTools output file

Then I calculated the effective couplings using the HEFT formula to get the couplings for the 5 neutral Higgses of the NMSSM with the gluon


NMSSMTools output file containing

The Reduced-Couplings

Modified translator 2.2

with the HEFT

formula

LHE file compatible with MG5 containing

the Effective-couplings

MadGraph5



𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝑐𝑜𝑢𝑝𝑙𝑖𝑛𝑔𝑠 = 𝑅𝑒𝑑𝑢𝑐𝑒𝑑 𝑐𝑜𝑢𝑝𝑙𝑖𝑛𝑔𝑠 × 𝑔ℎ 𝑐𝑜𝑢𝑝𝑙𝑖𝑛𝑔(SM)

After that, heft type term could be implemented in MadGraph5 (by B. Fuks)




Using SusHi:

Another tool to install and learn

SusHi stands for Supersymmetric Higgs, it is a computer code which calculates the cross sections in gluon fusion and bottom-quark annihilation in the SM and (N)MSSM for any neutral Higgs boson.

Using Hsushi script

I calculated the x-sections with MG5_aMCSushi at NLO for all the 5 Higgses and produced event samples


Delphes

Detector events

Pythia

Shower/Hadronize events

MadGraph Descripti

on of proton

using pdf

Matrix-element

Parton level

• Hsushi script

• SusHi NMSSM model at NLO

SusHi

• Run card

• Parameters card New

process directories

Decays table



This was produced in the B.1 scenario:

Mass of h = 124.6 GeV

Mass of Hs = 181.7 GeV

Mass of H = 322.6 GeV

Mass of As = 72.5 GeV

Mass of A = 311.7 GeV


MG5_aMCSusHi

4. Conclusions and perspectives

The chain of tools has been installed and closed to generate the

NMSSM Higgs events with MadGraph5 using SusHi

(MG5_aMCSusHi)

Now the real work can start to evaluate the benchmark points

In a future work, automatic transformation of the NMSSMTools

output file to MG5_aMCSusHi needs to be done; there is no script

available, another translate-type tool has to be created

SusHi doesn’t include the Higgs decays.

But decays can be done with Pythia using the decay-tables from

NMSSMtools

We will have to analyze larger data samples of NMSSM and SM-

background


Thank you for your attention


master defense 2015

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