# Presentation: 580388

## Physics at the High Energy Frontier

**J. Hewett                                                                              PANIC 2005**

## Primitive Thinker

**Primitive Thinker**

**Courtesy:  Y.K. Kim**

**Notes:**
These are the questions we started with which are I will call the primitive questions.

## Evolved Thinker

**Evolved Thinker**

**From “Quantum Universe”**

**Courtesy:  Y.K. Kim**

**Are there undiscovered principles of**
**    ****nature: New symmetries, new physical laws?**
**2. How can we solve the mystery of dark**
**    ****energy?**
**3. Are there extra dimensions of space?**
**4. Do all the forces become one?**
**5. Why are there so many kinds of particles?**
**6. What is dark matter?**
**    ****How can we make it in the laboratory?**
**7. What are neutrinos telling us?**
**8. How did the universe come to be?**
**9. What happened to the antimatter?**

**Notes:**
As our knowledge and thinking have evolved, we have built upon those initial questions.  Here I show you some of the questions that we are asking now that explore the phenomena in more detail.

## Collider Tools which Answer these Questions:

**LHC**:
**ILC**:

_**Collider Tools which Answer these Questions:**_

**proton**

**proton**

**e****-**

**e****+**

**Broad energy reach**
**Large event rate**

**Knowledge of initial**
**  ****quantum state**
**Well-defined initial **
**  ****energy and angular **
**  ****momentum (polarization)**
**Clean environment**
**Can vary CoM**

**Notes:**
Because of this feature, precise and model-independent measurements are a hallmark of linear collider physics, not possible in the complex experimental environment of the LHC.

## The LHC is Becoming a Reality!

**The excitement is building - we are counting down the days....**

## Major Discoveries are Expected!

**- A. De Roeck, Snowmass 2005**

## Slide 7

## Much Progress on the ILC in the Last Year:

_**Much Progress on the ILC in the Last Year:**_

**Superconducting rf Technology chosen **
**Global Design Effort Launched!**

**Barry Barrish is Director of the GDE**

**+ 3 Regional Directors**

**+ 45 Team Members and counting...**

**Baseline Configuration being Defined now...**

## Barrish, Snowmass 05

**Barrish, Snowmass 05**

## Barrish, Snowmass 05

**Barrish, Snowmass 05**

## Particles Tell Stories:   

_**Particles Tell Stories:**_**   **
**Discovery of a new particle is the opening chapter of a story.  These particles are merely the**** ****messengers which reveal**** ****a profound**** ****story about the nature of matter, energy, space****, ****and**** ****time****.**

_**Learning the full story involves**_**:**
** ****Discovery of a new particle**
** ****Discovery of the theory behind the new**** ****particle**

**It is up to us to find the new particles and to listen to their stories**

## Particles Tell Stories:   

_**Particles Tell Stories:**_**   **
**Discovery of a new particle is the opening chapter of a story.  These particles are merely the**** ****messengers which reveal**** ****a profound**** ****story about the nature of matter, energy, space****, ****and**** ****time****.**

_**Learning the full story involves**_**:**
** ****Discovery of a new particle**
** ****Discovery of the theory behind the new**** ****particle**

**Measurements at the ILC, together with results from the LHC, will**** ****identify the full nature of the physics at the TeV scale and reveal its full story**

**It is up to us to find the new particles and to listen to their stories**

## HEPAP LHC/ILC Subpanel Report(s):

**43 page semi-technical version, submitted to EPP2010 panel in late July**
- _[http://www.science.doe.gov/hep/LHC-ILC-Subpanel-EPP2010.pdf](http://www.science.doe.gov/hep/LHC-ILC-Subpanel-EPP2010.pdf)_
**35 page non-technical version, in press.**

**The report emphasizes:**
** ****the synergy between the LHC and **
**   ****ILC**
** ****differences in how measurements **
**   ****are made at ILC and LHC**
**unique physics to ILC**

## The Authors:

## The report centers on 3 physics themes:

** ****Mysteries of the Terascale****:  ****Solving the mysteries of matter at the Terascale**** **
** ****Light on Dark Matter****:  ****Determining what Dark Matter particles can be produced in the laboratory and discovering their identity**
** ****Einstein’s Telescope****:  ****Connecting the laws of the large to the laws of the small**

**Now for some highlights of physics unique to the ILC**

## Higgs at the Terascale

**An important Higgs production process is**
**    ****e****+****e****-**** ******** Z + Higgs**
**There are many possible final states, depending on how the Z and Higgs decay**

**In e+e- ******** Z + Anything**
**‘****Anything’ corresponds to a system **
**  ****recoiling against the Z  **
**The mass of this system is determined**
**  ****solely by kinematics and conservation**
**  ****of energy**
**because we see everything else, we**
**  ****know what is escaping**

**Recoil Technique****:**

**Peak in Recoil Mass corresponds to 120 GeV Higgs!**

## ILC Simulation for e+e-  Z + Higgs

- with Z  2 b-quarks and Higgs  invisible

**N. Graf**

## Recoil technique gives precise determination of Higgs properties Independent of its decay mode

**measurements of the Higgs couplings**

**Recoil technique gives precise determination of Higgs**** ****properties ****Independent**** ****of its decay mode**

**The strength of**** ****the Higgs couplings to fermions**
**  ****and bosons is given by the mass of the particle**
**Within the Standard Model this is a direct**
**  ****proportionality**

**This is a crucial test of whether a particle’s mass is generated by the Higgs boson!**

- Higgs

- f

- f

- -

**~ m****f**

## ILC will have unique ability to make model independent tests of Higgs couplings at the percent level of accuracy.

- Size of measurement errors

**ILC will have unique ability to make model independent tests of Higgs couplings at the percent level of accuracy.**

**m****h**** = 120 GeV**

## Higgs is Different!   

**This is the right sensitivity to discover extra dimensions, new sources of CP violation, or other novel phenomena**

**Mass (GeV)**

**m****h**** = 120 GeV**

**Coupling strength to Higgs boson**

_**Higgs is **__**Different!   **_
**First fundamental scalar to be discovered:  could be related to many things, even dark energy**

## Supersymmetry at the Terascale

**Determines**
**Quantum numbers (spin!)**
**Supersymmetric relation **
**  ****of couplings**

****

**= e**

****

**~**

**~**

**= 2e**

**-**

**Proof that it ****IS**** **
**Supersymmetry****!**

_**Supersymmetry at the Terascale**_

**M****1**** (GeV)**

**Ratio of Coupling Stregths**

**Selectron pair production**

**2% accuracy in **
**determination of Supersymmetric coupling strength**

## Precise Mass Measurements of Superpartners

**Example:  e ******** e + ******

**Fixed center of mass energy gives flat energy distribution in the laboratory for final state e****-**** **

**Endpoints can be used to determine superpartner masses to part-per-mil accuracy**

**~**

**~**

**e**

**A realistic simulation:**

**Determines Superpartner masses of the electron and photon to 0.05%!**

## A complicated Table with lots of details that illustrates how ILC results improve upon Superpartner mass measurements at the LHC

**A complicated Table with lots of details that illustrates how ILC results improve upon Superpartner mass measurements at the LHC**

**Shows accuracy of mass determinations at LHC and ILC alone and combined**

## Einstein’s Telescope to Unification

**Evolution of superpartner masses to high scale:**

**Force unification**

**Matter Unification**

_**Einstein’s Telescope to Unification**_

## Extra Dimensions at the Terascale

**Kaluza-Klein modes in a detector**

- 104

- 106

- 108

- 104

- 106

- 108

**Number of Events in e****+****e****-**** ******** ********+********-**

**For a conventional braneworld model with a single curved extra dimension of size ~ 10****-17 ****cm**

**For this same model embedded in a string theory**

- Standard Model Z-boson

- 1st KK mode

- 2nd KK mode

- 3rd KK mode

_**Extra Dimensions at the Terascale**_

## Detailed measurements of the properties of KK modes can determine:

**That we really have discovered additional**
**  ****spatial dimensions**
**Size of the extra dimensions**
**Number of extra dimensions**
**Shape of the extra dimensions**
**Which particles feel the extra dimensions**
**If the branes in the Braneworld have**
**  ****fixed tension**
**Underlying geometry of the extra**
**  ****dimensional space**

## Example:  Production of Graviton Kaluza-Klein modes in flat extra dimensions, probes gravity at distances of ~ 10-18 cm

**Production rate for e****+****e****-**** ******** ******** + Graviton **

- 104

- 105

- 106

**with**

**7**

**Extra Dimensions**

**6**

**5**

**4**

**3**

**2**

**Size of Measurement error**

**Measurement possible due to well-defined initial state & energy plus clean environment**

## Where particles live in extra dimensions

**Polarized Bhabha Scattering**

**Determines location of left- and right-handed electron in extra dimension of size 4 TeV****-1**

**Location of e****L**** in an extra dimension**

**Location of e****R**** in an extra dimension**

## Telescope to Very High Energy Scales 

_**Telescope to Very High Energy Scales **_

-    ‘**X’**

**Many tools to detect existence of heavy object ‘X’:**
**Deviations in production rates**
**Deviations in production properties such as**
**  ****distribution of angle from beam-line**
**Deviations in distributions of angular momentum**
**For all types of final state fermions!**

**ILC can probe presence of Heavy Objects with **
**Mass > Center of Mass Energy in e****+****e ******** ff**

****** ****Indirect search for New Physics**

**-**

## Example:  New Heavy Z-like Boson from Unification Theories

**For ILC Sensitivity****:**
**Solid = 5******** ****= standard discovery**
**                         ****criteria**
**Dashed = 2******

**95% (=2********) direct discovery at LHC**

_**Example:**_**  New Heavy Z-like Boson from Unification Theories**

**Collider Sensitivity**** **

- Mass of Z-like Boson (TeV)

**ILC can probe masses many times the machine energy!**

## 95% contours for Z’ couplings to leptons at ILC

**LHC determines mass**
**ILC determines interactions**

**Number of Events in pp ******** ********+********-**

**Mass of muon pair (TeV)**

**Axial Coupling**

**Vector Coupling**

**Kaluza-Klein Z’**

**SO(10): origin of ******** mass**

**E****6****: unified Higgs**

**Drell-Yan distribution at LHC**

## Light on Dark Matter 

**Dark Matter comprises 23% of the universe**
**No reason to think Dark Matter should be simpler **
**  ****than the visible universe ******** likely to have many **
**  ****different components**
**Dream:  Identify one or components and study it in**
**  ****the laboratory**

## One Possibility:  Dark Matter in Supersymmetry

**  ****Neutralino of Supersymmetry**
**      ****- stable and neutral with mass ~ 0.1 – 1 TeV**
**In this case, electroweak strength annihilation gives**
**  ****relic density of**** **

**                    ****m****2**
**Ω****CDM**** h****2**** ~ **
**                 ****(1 TeV)****2**

_**One Possibility**__**:  **__**Dark Matter in Supersymmetry**_

## Comparative precision of ILC measurements (within SUSY)

**ILC and Astro measurements**

**ILC and direct detection**

## Slide 35

## The more discoveries that are made at the LHC, the greater the discovery potential at the ILC

## The more discoveries that are made at the LHC, the greater the discovery potential at the ILC

**When the LHC makes its discoveries, let’s be ready to start construction on the ILC!**** **