prospects for observation of dark matter and extra...

Moriond-La Thuile 2009 Moriond-La Thuile 2009 11P. Vanlaer (ULB) P. Vanlaer (ULB)

Prospects for Observation of Dark Matter and Extra Dimensions in CMS

P. VanlaerIIHE - Université Libre de Bruxelleson behalf of the CMS collaboration

Moriond-La Thuile 2009Very High Energy Phenomena in the Universe

●Short phenomenology introductionShort phenomenology introduction●The CMS experiment at the LHCThe CMS experiment at the LHC●Early SUSY searchesEarly SUSY searches●Extra d imension searchesExtra d imension searches


● Extensions of the Standard Model introduced for reasons independent of Dark Matter (hierarchy problem) include new particles such as:● LSP – neutralino 0

1

● LKP from e.g. universal extra dimensions● These are good Dark Matter candidates

● 100 GeV < M < few TeV● Neutral, stable● Annihilation cross-section O(1 pb) - appropriate relic density

Introduction

LHC allows tes t s of BSM at th e TeV scaleLHC allows tes t s of BSM at th e TeV scaleGen er ic s ign atu re for DM search es :Gen er ic s ign atu re for DM search es :

gg,qg,qqgg,qg,qq m iss in g Em iss in g ETT + jet s (+ lep ton s ) + jet s (+ lep ton s )


Signals and backgrounds

SignalsSignals

BackgroundsBackgrounds

Top quark: ~1 nb

WlZ: ~20/12 nb

Jets (q, g): ~b

SUSY (M~500 GeV): ~10 pbZ'(M~1 TeV)l+l-: ~1 pbsteeply falling with M

Zl+l-: ~2 nb

Cross-sections at s = 14 TeV

●Select ivity 1 ,000- 1 ,000 ,000Select ivity 1 ,000- 1 ,000,000●Con t rol backgrou n d from d ataCon t rol backgrou n d from d ata


The CMS experiment

TrackerTracker

EcalEcal

HcalHcal

SolenoidSolenoid

MagnetMagnet

TrackerTracker

Hcal

Muon Muon systemsystem

●Efficien t (~ 90%) detection of Eff icien t (~ 90%) detection of isolated m uons and electrons up isolated m uons and electrons up to |to | |<2.4 (~ 10|<2.4 (~ 10 oo to beam to beam ))●Mis- iden tif ication rate of jets as Mis- iden tif ication rate of jets as leptons <10leptons <10 - 4- 4

●Energy resolu tion at 100 GeV Energy resolu tion at 100 GeV ~ 1% for ~ 1% for ~ 0.5% for e/~ 0.5% for e/

●Herm etic calorim eters, Herm etic calorim eters, coverage up to |coverage up to | |<5 (0.8|<5 (0.8 o o to to beam )beam )●Jet energy resolu tion~ 10% at Jet energy resolu tion~ 10% at 100 GeV100 GeV●MET resolu tion <5% above MET resolu tion <5% above EE

TT=200 GeV=200 GeV


CMS tests in cosmic rays

Detector closed in July 2008~650.106 cosmic muons collected, 290.106 with B=3.8 T

Blue crosses: measured energy loss in HCAL (left) and ECAL (right) vs. momentum of muon measured in MUON+TRACKER, compared to simulations

Calibration of all systems ~OK !


● September 10 - beam with 2.109 450 GeV protons dumped on collimator 150m upstream

CMS first beam data

Energy d ep osited Energy d ep osited in HCALin HCAL

Correlat ion bw. Energy Correlat ion bw. Energy reconst ructed in HCAL reconst ructed in HCAL barrel and ECAL barrelbarrel and ECAL barrel

DebrisDebrism uonsm uons

● Possible LHC schedule for 2009 – recommendations to CERN management from Chamonix workshop (Feb.6)● 200pb-1 per experiment, at 10TeV● Physics runs in late 2009, run through winter

● ~100 magnets cannot be retested in cold until September


CMS performance summary JINST 3 S08004 (2008)

MET resolu t ionMET resolu t ionJME- 07- 001- PASJME- 07- 001- PAS

ECAL energy resolu t ionECAL energy resolu t ionTest BeamTest Beam

3x3 crys tal area3x3 crys tal area

TrackerTrackerMuon sys temMuon systemCom bined pCom bined p

TT resolu t ion resolu t ion

Jet EJet ETT resolu t ion resolu t ion


Discovering SUSY

● MET+multi-jets analysisMET > 200 GeVMET > 200 GeV 3 h igh - p3 h igh - p

TT jets jets

(MET- jets )(MET- jets )Ind irect lep ton vetoInd irect lep ton veto

HHTT > 500 GeV > 500 GeV

● Di-jet analysis● Angular observables, e.g.

CMS PAS SUS- 08- 005CMS PAS SUS- 08- 005


Discovering SUSYSummary all channels - mSugra

LHC , 14TeVLHC , 14TeV1 year at 101 year at 10 3232 cm cm - 2- 2ss - 1- 1


Kinematic edges

● Cascade decay, e.g. at LM1:

● Characteristic shape of ml+l-

● Edge extracted from fit of NS and N

B using signal model

+ measured background shape

CMS PAS SUS- 08- 001CMS PAS SUS- 08- 001++ -- , LM1, 1fb, LM1, 1fb - 1- 1


Extra dimensionsphenomenology

● Deviations from Standard Model continuum

● In MET+monojet, MET+

● In qqZ/l+l- mass spectrum (Drell-Yan)

● Narrow resonance

● In ml+l-

spectrum

● In m spectrum

● High-multiplicity, spherical event

● SUSY-like with MET+soft multi-leptons+jets...

Sign atu resSign atu res● Sub-millimeter (ADD)

● Light Graviton Kaluza-Klein tower

● Micro-Black Hole

● Randall-Sundrum

● Heavy KK Graviton state

● TeV-1

● Heavy Z'/' (KK state but also GUT,...)

● Universal

Mod elsMod els


MET+monojet● ADD model

● new dimensions of size R~0.1mm, compactified on a scale M

D ~ 1 TeV ~ EWK scale

● Dilutes gravity at r<<R so that Planck scale M

Planck~M

D

● Tower of light Graviton Kaluza-Klein states, escapes detection

● After 100pb-1, current limits on M

D doubled

MET > 400 GeVMET > 400 GeV h igh- p h igh - p

TT jet jet

(MET- jet )(MET- jet)Ind irect lep ton vetoInd irect lep ton veto

Z(Z()+ jets background )+ jets background m easured m easu red

from from W(W()+ jets)+ jetscom plem ent to Z()+jets

MD reach

(TeV)

CMS PAS EXO- 08- 011CMS PAS EXO- 08- 011

CMS PAS EXO- 08- 011CMS PAS EXO- 08- 011CMS PAS SUS- 08- 002CMS PAS SUS- 08- 002


Resonance in ml+l-

ee++ ee --

ZZSSMSSM

ZZ

● High-pT leptons, seek peak

● Measure high-mass DY as control

● Data-driven background subtraction● tt (“ e”, b-tag); jets (fake rate)



RS Graviton

● 10fb-1: all parameter space covered● 100fb-1: spin discrimination

ZZALRMALRM

Drell- YanDrell- YanGravitonGraviton


Conclusions

● CMS detector works beautifully● Analyses well prepared

● Including data-driven methods for selection efficiencies and backgrounds

● Plans:● Identify any signature we might have missed● Take data!

● References● CMS Physics results:

● CMS Physics TDR Vol.II, J.Phys.G: Nucl.Part.Phys 34 (2007) 995

● “ The CMS experiment at the CERN LHC” , JINST 3 S08004 (2008)

h t tp s :/ / twiki.cern .ch / twiki/ / b in / view/ CMS/ Ph ys icsResu lt sh t tp s :/ / twiki.cern .ch / twiki/ / b in / view/ CMS/ Ph ys icsResu lt s

Cred it s to M.Felcin i,M.Moz er and C.Delaere for s lid es m aterial


CMS closed – July 2008


Backu p


Reduced LHC energy


SUSY cross-sections and branching ratios


SUSY limit in jets+MET


mUED● KK parity conserved● (1), (1) possible DM candidates

● Pair-production of g(1), q(1)

● SUSY-like cascade with 4 soft l+/-, soft jets and LKP escaping detection

● Compactification radius R-1 constrained from EWK data; >300-600 GeV

CMS Note 2006/ 008CMS Note 2006/ 008

2e22e2


Dark matter in SUSY -the neutralino

● Dark matter: relic density of WIMPs (M>100 GeV)● Candidate in many SUSY models: the lightest neutralino

01

● At the LHC: copious pair production of squarks and gluinos if M

sq,sg< 1TeV

SUSY s ign atu re:SUSY s ign atu re:Large m iss in g t ran sverse en ergyLarge m iss in g t ran sverse en ergy

+ m u lt i- jet (+ lep ton s )+ m u lt i- jet (+ lep ton s )


● Cascade decay into jets and 0


Discovering SUSY

● Generic signatures are identified from simulations of benchmark models (e.g. mSugra)

● Large MET+jets+leptons● Topologies and cross-sections vary



Event yield for MSUGRA LM1, 1fbEven t yield for MSUGRA LM1, 1fb - 1 -- 1 -

● Different approach: di-jet analysis● Exactly 2 jets with E

T>50GeV

● Indirect lepton veto● Robust angular observable

T


Discovering SUSY (2)

j1 ,j2j1 ,j2


Resonance in ml+l-

ee++ ee --

ZZSSMSSM

ZZ

● High-pT leptons, seek peak

● Measure high-mass DY as control

● Data-driven background subtraction● tt (“ e”, b-tag); jets (fake rate)



L1 Overview


Trigger in Practice

Most of the HLT Most of the HLT functionalities testedfunctionalities tested

Global Run Global Run July 0 8July 0 8

● Online reconstruction(CPU performance, memory footprint)

● High rate tests (random triggerup to ~80kHz)

● L1 seed to HLT● Streaming calibration data (reduced event content) parallelto full events

● Complete chain of data transfer up to Tier0 at CERN


Discovering SUSY

● Inclusive MET+multi-jets analysis● MET > 200 GeV● 3 jets

● ET > 180,110,30 GeV

● Indirect lepton veto● Cuts on between MET and jets

● HT = E

T,jets+MET > 500 GeV

CMS Physics TDR Vol.IICMS Physics TDR Vol.IIJ.Phys.G:Nucl.Par t .Phys 34 (2007) 995J.Phys.G:Nucl.Par t .Phys 34 (2007) 995

LHC LHC 1y at 101y at 10 3232 cm cm - 2- 2ss - 1- 1


● Di-jet analysis● Exactly 2 jets with E

T>50GeV

● Indirect lepton veto● Robust angular observable:


Discovering SUSY

● Inclusive MET+multi-jets analysis● MET > 200 GeV● 3 jets in ||<1.7

● ET > 180,110,30 GeV


● HT = E


CMS Physics TDR Vol.IICMS Physics TDR Vol.IIJ.Phys .G:J.Phys .G:

Nucl.Par t .Phys 34 (2007) 995Nucl.Par t .Phys 34 (2007) 995

Even t yield for MSUGRA LM1, 1fbEven t yield for MSUGRA LM1, 1fb - 1- 1

● Data-driven background estimation of Z()+jets● From Z(ee)+jets: 5% precision after 1fb-1

● For 100pb-1 analyses: larger statistics from +jets and W+jets● CMS PAS SUS-08-002



Discovering SUSY

● Inclusive MET+multi-jets analysis● MET > 200 GeV● 3 jets in ||<1.7

● ET > 180,110,30 GeV


● HT = E


LHC LHC 1y at 101y at 10 3232 cm cm - 2- 2ss - 1- 1

● Data-driven background estimation of Z()+jets● From Z(ee)+jets: 5% precision after 1fb-1

● For 100pb-1 analyses: larger statistics from +jets and W+jets● CMS PAS SUS-08-002


Interim Summary Report on the analysis of the 19th September 2008 incident at the LHC

Incident during poweringIncident during powering

The m agnet circu it s in the seven other sectors of the LHC had been fu lly com m iss ioned The m agnet circu it s in the seven other sectors of the LHC had been fu lly com m iss ioned to their nom inal cu rren ts (correspond ing to beam energy of 5.5 TeV) before the firs t to their nom inal cu rren ts (correspond ing to beam energy of 5.5 TeV) before the firs t beam in ject ion on 10 Sep tem ber 2008. For the m ain d ipole circu it , th is m ean t a p owering beam in ject ion on 10 Sep tem ber 2008. For the m ain d ipole circu it , th is m ean t a p owering in s tages u p to a cu rren t of 9.3 kA. The d ipole circu it of sector 3- 4, the las t one to be in s tages u p to a cu rren t of 9 .3 kA. The d ipole circu it of sector 3- 4, the las t one to be com m iss ioned , had on ly been powered to 7 kA p rior to 10 Sep tem ber 2008. After the com m iss ioned , had on ly been powered to 7 kA p rior to 10 Sep tem ber 2008. After the successfu l in ject ion and circu lat ion of the firs t beam s at 0 .45 TeV, com m iss ion ing of th is successfu l in ject ion and circu lat ion of the firs t beam s at 0 .45 TeV, com m iss ion ing of th is sector u p to the 5.5 TeV beam energy level was resum ed as p lanned and accord ing to sector u p to the 5.5 TeV beam energy level was resum ed as p lanned and accord ing to es tablished p rocedu res .es tablished p rocedu res .

On 19 Sep tem ber 2008 m orn ing, the cu rren t was being ram ped up to 9.3 kA in the m ain On 19 Sep tem ber 2008 m orn ing, the cu rren t was being ram ped up to 9.3 kA in the m ain d ip ole circu it at the nom inal rate of 10 A/ s , when at a value of 8.7 kA, a res is t ive z one d ip ole circu it at the nom inal rate of 10 A/ s , when at a value of 8.7 kA, a res is t ive z one developed in the elect rical bu s in the region between d ipole C24 and quad ru pole Q24. developed in the elect rical bu s in the region between d ipole C24 and quad ru p ole Q24. The firs t evidence was the ap p earance of a voltage of 300 m V d etected in the circu it The firs t evidence was the app earance of a voltage of 300 m V d etected in the circu it above the noise level: the t im e was 11:18:36 CEST. No res is t ive voltage app eared on the above the noise level: the t im e was 11:18:36 CEST. No res is t ive voltage app eared on the d ip oles of the circu it , ind ivid ually equ ip ped with qu ench d etectors with a detect ion d ip oles of the circu it , ind ivid ually equ ip p ed with qu ench d etectors with a detect ion sens it ivity of 100 m V each , so that the quench of any m agnet can be exclud ed as in it ial sens it ivity of 100 m V each , so that the quench of any m agnet can be exclud ed as in it ial even t . After 0 .39 s , the res is t ive voltage had grown to 1 V and the p ower converter , even t . After 0 .39 s , the res is t ive voltage had grown to 1 V and the p ower converter , unable to m ain tain the cu rren t ram p , t r ipp ed off at 0 .46 s (s low d ischarge m od e). The unable to m ain tain the cu rren t ram p , t r ipp ed off at 0 .46 s (s low d ischarge m od e). The cu rren t s tar ted to d ecrease in the circu it and at 0 .86 s , the energy d ischarge switch cu rren t s tar ted to d ecrease in the circu it and at 0 .86 s , the energy d ischarge switch opened , inser t ing du m p res is tors in the circu it to p rodu ce a fas t power abort . In th is opened , inser t ing du m p res is tors in the circu it to p rodu ce a fas t p ower abort . In th is sequence of even ts , the qu ench detect ion , p ower converter and energy d ischarge sys tem s sequence of even ts , the qu ench detect ion , p ower converter and energy d ischarge sys tem s behaved as exp ected .behaved as exp ected .

3131


Sequence of events and consequencesSequence of events and consequences

With in the firs t second , an elect r ical arc d evelop ed and p unctu red the helium With in the firs t second , an electr ical arc d evelop ed and p unctu red the helium enclosu re, lead ing to release of helium in to the insu lat ion vacuum of the enclosure, lead ing to release of helium in to the insu lat ion vacuum of the cryostat .cryostat .

The sp r ing- load ed relief d iscs on the vacuum enclosu re op ened when the The sp r ing- load ed relief d iscs on the vacuum enclosu re op ened when the p ressure exceed ed atm osp heric, thus relieving the helium to the tunnel. They p ressu re exceed ed atm osp heric, thus relieving the helium to the tunnel. They were however unable to con tain the p ressu re r ise below the nom inal 0 .15 MPa were however unable to con tain the p ressure r ise below the nom inal 0 .15 MPa absolu te in the vacuum enclosures of subsector 23- 25, thus resu lt ing in large absolu te in the vacuum enclosu res of subsector 23- 25, thus resu lt ing in large p ressure forces act ing on the vacuum barr iers sep arat ing neighboring p ressu re forces act ing on the vacuum barr iers sep arat ing neighboring subsectors , which m ost p robably d am aged them . These forces d isp laced subsectors , which m ost p robably d am aged them . These forces d isp laced d ip oles in the subsectors affected from their cold in ternal sup p orts , and d ip oles in the subsectors affected from their cold in ternal sup p orts , and knocked the Short St raigh t Sect ion cryostats housing the quad rup oles and knocked the Short Straigh t Sect ion cryostats housing the quad rup oles and vacuum barr iers from their external sup p ort jacks at p os it ions Q23, Q27 and vacuum barr iers from their external sup p ort jacks at p os it ions Q23, Q27 and Q31, in som e locat ions breaking their anchors in the concrete floor of the Q31, in som e locat ions breaking their anchors in the concrete floor of the tunnel. The d isp lacem ent of the Short Straigh t Sect ion cryostats also d am aged tunnel. The d isp lacem ent of the Shor t St raigh t Sect ion cryostats also d am aged the “jum p er” connect ions to the cryogen ic d is t r ibu t ion line, bu t withou t the “jum p er” connect ions to the cryogen ic d is t r ibu t ion line, bu t withou t rup tu re of the t ransverse vacuum barr iers equ ip p ing these jum p er rup tu re of the t ransverse vacuum barr iers equ ip p ing these jum p er connect ions , so that the insu lat ion vacuum in the cryogen ic line d id not connect ions , so that the in su lat ion vacuum in the cryogen ic line d id not d egrad e.d egrad e. 3232


Inspection and diagnosticsInspection and diagnostics

Th e n u m ber of m agn ets to be rep aired is a t m axim u m of 5 Th e nu m ber of m agn ets to be rep aired is at m axim u m of 5 qu ad ru p oles (in Sh or t St raigh t Sect ion s) an d 24 d ip oles , bu t it is likely qu ad ru p oles (in Sh or t St raigh t Sect ion s) an d 24 d ip oles , bu t it is likely th at m ore will h ave to be rem oved from th e tu n n el for clean in g an d th at m ore will h ave to be rem oved from th e tu n n el for clean in g an d exch an ge of m u lt ilayer in su lat ion . Th e exact nu m bers will be kn own exch an ge of m u lt ilayer in su lat ion . Th e exact n u m bers will be kn own on ce th e on going in sp ect ion s are com p leted on ce the on goin g in sp ect ion s are com p leted (n ow kn own 39 d ip oles (n ow kn own 39 d ip oles an d 14 SSS). an d 14 SSS). Sp are m agn ets and sp are com p on en ts ap p ear to be Sp are m agn ets an d sp are com p on en ts ap p ear to be available in ad equ ate typ es an d su fficien t qu an t it ies for a llowin g availab le in ad equ ate typ es an d su fficien t qu an t it ies for allowin g rep lacem en t of th e d am aged on es d u r in g th e for th com in g sh u td own . rep lacem en t of the d am aged on es d u r in g th e for th com in g sh u td own . Th e exten t of con tam in at ion to th e beam vacu u m p ip es is n ot yet Th e exten t of con tam in at ion to th e beam vacu u m p ip es is n ot yet fu lly m ap p ed , bu t kn own to be lim ited ; in s itu clean in g is bein g fu lly m ap p ed , bu t kn own to be lim ited ; in s itu clean in g is bein g con s id ered to keep to a m in im u m th e n u m ber of m agn ets to be con s id ered to keep to a m in im u m th e n u m ber of m agnets to be rem oved . Th e p lan for rem oving/ rein s ta lla t ion , t ran sp ort an d rep air rem oved . Th e p lan for rem ovin g/ rein s tallat ion , t ran sp or t an d rep air of m agn ets in sector 3- 4 is bein g es tab lish ed and in tegrated with th e of m agn ets in sector 3- 4 is bein g es tablish ed an d in tegrated with th e m ain ten an ce an d con solid at ion work to be p erform ed d u r in g th e m ain ten an ce an d con solid at ion work to be p erform ed d u rin g th e win ter shu td own . Th e corresp ond in g m an p ower resou rces h ave been win ter sh u td own . The corresp on d in g m an p ower resou rces h ave been secu red .secu red .

All m agnets with soot in the beam pipe will be rem oved. M agnets with M LI in All m agnets with soot in the beam pipe will be rem oved. M agnets with M LI in

the beam pipe will be cleaned insitu.the beam pipe will be cleaned insitu. 3333

Busbar splice

Cable Junction Box Cross-section

Upper Tin/Silver Soldering alloy Layer

Inter-Cable Tin/Silver Soldering Alloy Layer

Superconducting Cable in Copper

Stabilizer

Upper Copper Profile

Lower Copper U Profile

Lower Tin/Silver Soldering Alloy Layer

Completed Junction

3434

Busbar splice

3535

Magnet cooling scheme

3636

Cryostat and cold masses longitudinal displacements

Courtesy JP. TockCourtesy JP. Tock3737

Conclusions (III)

The repowering and investigations performed in sectors 1- 2, 6- 7 and 7- 8 were very successful

There is no excessive splice resistance in the dipole bus- bars in suspicious cryo-cell 15- 16 of sector 1- 2

– Perfect (nominal) splice resistances of 0.35 nΩ were measured

An excessive resistance inside dipoles B16.R1, B32.R6 was detected

– The electrical resistance, estimated by two independent methods, is of the order of 100 and 47 nΩ

Investigations performed in sector 1- 2 resulted in development of powerful calorimetric and electric methods to detect and monitor excessive resistances in the main LHC magnet circuits

– These methods will be further improved and applied as dedicated procedures

during the machine commissioning and operation. The electrical method will

include the busbar splice.

3838

The plan for 2009

JanJan FebFeb MarMar AprApr MayMay JunJun JulJul AugAug

Last m agnet Last m agnet

goes into sector goes into sector

3434

LHC coldLHC cold

20092009

DecDec

Rem oval of dam aged m agnetsRem oval of dam aged m agnets

Cleaning and repairCleaning and repair

Cold testingCold testing

ReinstallationReinstallation

InterconnectionInterconnection

Pressure testingPressure testing

Cool downCool down

3939

Outcome Chamonix Workshop

Message from D.G. Rolf Heuer to CERN personnel, Feb.6, 2009Message from D.G. Rolf Heuer to CERN personnel, Feb.6, 2009

Many issues were tackled in Cham on ix th is week, and im p ortan t recom m end at ions Many issues were tackled in Cham on ix th is week, and im p ortan t recom m end at ions m ad e. Und er a p rop osal subm it ted to CERN m anagem en t , we will have p hysics d ata in m ad e. Und er a p rop osal subm it ted to CERN m anagem ent , we will have p hysics d ata in late 2009, and there is a s t rong recom m end at ion to run the LHC th rough the win ter and late 2009, and there is a s t rong recom m end at ion to run the LHC th rough the win ter and on to au tum n 2010 un t il we have substan t ial quan t it ies of d ata for the exp erim en ts . on to au tum n 2010 un t il we have substan t ial quan t it ies of d ata for the exp erim ents . With th is change to the sched u le, ou r goal for the LHC's firs t runn ing p er iod is an With th is change to the sched u le, ou r goal for the LHC's firs t runn ing p er iod is an in tegrated lum inosity of m ore than 200 p b- 1 op erat ing at 5 TeV p er beam , su fficien t in tegrated lum inosity of m ore than 200 p b- 1 op erat ing at 5 TeV p er beam , su fficien t for the firs t new p hysics m easu rem en ts to be m ad e. Th is , I believe, is the best p oss ible for the firs t new p hysics m easurem en ts to be m ad e. Th is , I believe, is the best p oss ible scenario for the LHC and for p ar t icle p hysics . scenario for the LHC and for p ar t icle p hysics .

There were d iscuss ions in Cham on ix between accelerator and d etector p hysicis ts on There were d iscussions in Cham on ix between accelerator and d etector p hysicis ts on several im p ortan t issues . Agreem ents were reached whereby team s d rawing from both several im p ortan t issues . Agreem en ts were reached whereby team s d rawing from both com m unit ies will work together on im p ortan t subjects , such as the d etailed analys is of com m unit ies will work together on im p ortan t subjects , such as the d etailed analysis of m easu rem en ts m ad e d u ring tes t ing of m agnets on the su rface. m easurem en ts m ad e d uring tes t ing of m agnets on the su rface.

Since the incid en t , enorm ous p rogress has been m ad e in d evelop ing techn iques to Since the incid en t , enorm ous p rogress has been m ad e in d evelop ing techn iques to d etect any sm all anom aly. These will be u sed in ord er to get a com p lete p ictu re of the d etect any sm all anom aly. These will be u sed in ord er to get a com p lete p ictu re of the res is tance in the sp lices of all m agnets ins talled in the m ach ine. Th is will allow res is tance in the sp lices of all m agnets in stalled in the m ach ine. Th is will allow im p roved ear ly warn ing of any ad d it ional susp icious sp lices d u ring op erat ion . The early im p roved ear ly warn ing of any ad d it ional susp icious sp lices d u ring op erat ion . The ear ly warn ing system s will be in p lace and fu lly tes ted before res tar t ing the LHC. warn ing sys tem s will be in p lace and fu lly tes ted before res tar t ing the LHC.


Another im p or tan t top ic for the fu tu re was the rad iat ion hard ness of elect ron ics Another im p ortan t top ic for the fu tu re was the rad iat ion hard ness of elect ron ics ins talled in the service areas and the tunnel. For m any years , p ar t icle d etector ins talled in the service areas and the tunnel. For m any years , p ar t icle d etector electron ics have been d es igned to cop e with even ts such as loss of beam in to the elect ron ics have been d esigned to cop e with even ts such as loss of beam in to the d etectors . Unt il now, th is has not been necessary for the accelerators , bu t will becom e d etectors . Unt il now, th is has not been necessary for the accelerators , bu t will becom e so when the LHC m oves to h igher beam in tens ity and lum inos ity. Again , with d etector so when the LHC m oves to h igher beam in tens ity and lum inosity. Again , with d etector and accelerator p hysicis ts working closely together , the exp erience gained from the and accelerator p hysicis ts working closely together , the exp erience gained from the d etectors can be ap p lied to the LHC itself. d etectors can be ap p lied to the LHC itself.

As the Bullet in rep orted on 30 January, op en ing up a m agnet in wh ich an anom alously As the Bullet in rep or ted on 30 January, op en ing up a m agnet in wh ich an anom alously h igh electr ical res is tance was m easu red m ad e the reason for the anom aly im m ed iately h igh elect r ical res is tance was m easured m ad e the reason for the anom aly im m ed iately obvious - a sp lice had not been correct ly m ad e. Th is is one of two such sp lices that obvious - a sp lice had not been correct ly m ad e. Th is is one of two such sp lices that were id en t ified in the five sectors tes ted , and as a resu lt the m agnet con tain ing the were id en t ified in the five sectors tes ted , and as a resu lt the m agnet con tain ing the second will also be rem oved from the tunnel for rep air . Since resis tance tes ts can on ly second will also be rem oved from the tunnel for rep air . Since resis tance tes ts can on ly be cond ucted in cold m agnets , th ree sectors rem ain to be tes ted : sector 3- 4 where the be cond ucted in cold m agnets , th ree sectors rem ain to be tes ted : sector 3- 4 where the original incid en t occurred and the sectors on either s id e. With in sector 3- 4, the 53 original incid en t occurred and the sectors on either s id e. With in sector 3- 4, the 53 m agnets that are being rep laced in the tunnel will all be tes ted before cool d own , and m agnets that are being rep laced in the tunnel will all be tes ted before cool d own, and the sectors either s id e will be cooled d own ear ly enough to in tervene if necessary with the sectors either s id e will be cooled d own ear ly enough to in tervene if necessary with no im p act on the sched u le. Th is leaves around 100 d ip ole m agnets that we'll not be no im p act on the sched u le. Th is leaves around 100 d ip ole m agnets that we'll not be able to tes t un t il Sep tem ber and a corresp ond ingly sm all chance that we m ay find able to tes t un t il Sep tem ber and a corresp ond ingly sm all chance that we m ay find fu r ther bad sp lices that will need to be rep aired before op erat ion s tar ts . fu r ther bad sp lices that will need to be rep aired before op erat ion s tar ts .


The Cham on ix workshop involved a lot of work by m any p eop le. Much p rogress has The Cham onix workshop involved a lot of work by m any p eop le. Much p rogress has been m ad e, and the m anagem en t now has all it need s to m ake an in form ed d ecis ion been m ad e, and the m anagem en t now has all it need s to m ake an in form ed d ecis ion next Mond ay on LHC res tar t . I'd like to thank all those involved , and I will be writ ing to next Mond ay on LHC res tar t . I'd like to thank all those involved , and I will be writ ing to you again ear ly next week to let you know our d ecis ion . you again ear ly next week to let you know our d ecis ion .

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