production cross sections for anti-p and anti-d with ... · production cross sections for anti-p...

Productioncrosssectionsforanti-pandanti-d

withCOMPASS++/AMBER

P.ZucconTrentoUniversityandINFNTIFPA

M.Chiosso,O.DenisovTorinoUniversityandINFNTorino

N.MasiINFNBologna

2nd Cosmic-rayAntideuteron WorkshopUniversityofCalifornia– LosAngeles

Weleftheretwodaysago!

P.Zuccon- TrentoUniversity dbar19- UCLA 2

AMSMeasurementofanti-p/pratio

Twomajoruncertaintieslimitthepredictionoftheanti-pfluxfromCRinteractionwithISM• productioncrosssectionsp-p->pbar +Xp-He->pbar +X• CRpropagationinthegalaxy

Introduction


Fractionoriginofanti-pfromCRinteractionwithISM

Mar

tin W

. Win

kler

(Sto

ckho

lm

Uni

vers

ity)

LHCb-CONF-2017-002 Measurementperformedat7TeVp-He->pbar +X

NA61p+p data beammomentaof20,31,40,80,and158GeV/cEur.Phys.J.C77,671(2017)

• anti-pproductioncrosssectionfromp-pandp-Heinteractionsispoorlymeasuredandcannotsimplyconstrainedfromavailablemeasurements.

• anaccuratepredictionoftheexpectedanti-pfluxincosmicraysintherigidityrangefromfewGeVtoseveralhundredsofGeVs,isinterestingtounderstandcosmicrayandpossiblysearchforsignalsofnewphysics

• LHC-bcollaborationreportedameasurementtheanti-pXSfrom8TeV p-He,andforeseeasimilarmeasurementwith4TeVprotons.

• NA61publishedp-ptoanti-pat20,31,40,80,and158GeV/c

• wewanttoinvestigatethepossibilitytoperformameasurementwiththeSPSprotonsbetween50and280GeV/confixedLH2andLHe targets,andamagneticspectrometer

COMPASS@CERN


Acceptance:+/- 180mrad+/- 10deg2.4 < h < 8

FistStep


UseFLUKAtosimulatep-pandp-Heinteractionswithabeamof190GeV/c

momentum.

p-LH2eventfeatures@190GeV/c


3.05105 interactingevents

allZ!=0

anti-p#anti-p

Mean0.72

p-LHe eventfeatures@190GeV/c


2.25105 interactingevents

allZ!=0

anti-p#anti-p

Mean0.77

Secondstep


• UseFLUKAgeneratedinteractionasinputfortheofficialCOMPASSGeant 4simulation(TGEANT)

• PasstheproducedfilesthroughtheofficialCOMPASSreconstructionsoftware

COMPASSsimulation(p-p190GeV)


MC DATA

Numberoftracks(q <10deg)

VertexpositionVertexresolution

COMPASSRecaccuracy


COMPASSsimulation(p-p190GeV)


Antiprotontrackingefficiency

GeV)10

Momentum (log1− 0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

)ηPs

eudo

repi

dity

(

11.5

22.5

33.5

44.5

55.5

66.5

77.5

88.5

99.510

10.511

11.5

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

RICHAcc

Pseudo-rapidityvslog10(momentum)

Thirdstep


EstimateRICHparticleidentificationperformancefromp-pdataalreadycollectedat190GeV

Selectpuresamplesofp,pbar,p+andp-


SelectasampleofV0• twotracksformingavertex• p=p1+p2pointstotheprimaryvertex

Armenteros plot

alpha=pl1-pl2/(pl1+pl2)

K0

L0anti-L0Aftercleanup(mindist,primang)

gamma

DATASETcollectedin2009(p-LH2)

Massselection


LambdaMass

Kaonmass

SelectedTracksfromK0 andL0


Individual“pure”samples


pi- pi+

ppbar

RICHanglevsbg


pi- pi+

ppbar

GaussianFitoftheRICHangle


pi+pi-

pi+pi-

pi+pi-p

pi+pi-p

MPV MPV

sigmasigma

mrad

mrad

UniversalRICHresponsefunction


betaRICH

bg (tracking)

anti-pandpareidentifiedabovethreshold(~18GeV/c)withanefficiency>95%upto~60(GeV/c)FromtheKaonthreshold(~9GeV/c)tothepthreshold,pandanti-pareidentifiedusingRICHinvetomode.

anti-pspectrum@190GeV/c

Fourthstep


Combinetheelementstoobtainacrosssectionmeasurement

Crosssectionmeasurement

• Strategy• Countallthep-p(orp-He)interactioninthetarget(𝑅")• Identifyeventswithone(ormultiple)anti-pvsreconstructedmomentumandangle(𝑅#(𝑝, 𝜃))

• Calculatethedoubledifferentialcrosssectionas

𝑑𝜎,-𝑑𝑝𝑑𝜃 =

𝑅# 𝑝, 𝜃𝑅"

• Severalpossiblepitfallsandsourcesofsystematicerrors!


CompassTriggersystem


Ratestatisticsandpileup• Typicalbeamintensityis5107 pfora9.8sspill

• Weexpect~5.4%oftheprotonstointeractwiththe40cmLH2targetà ~270k interaction/s

• CompassstandardtriggerDT0is𝐵𝑇&𝐵𝐾&𝑆𝑎𝑛𝑑𝑤𝑖𝑐ℎ𝑉𝑒𝑡𝑜&𝑅𝑃𝐷

• Thisreducethetriggerrateto33kHzwhichcanbehandledbytheCOMPASSDAQ

• Forthefuturemeasurementswewillasktoreducethebeamintensityto5106 andplantousethetrigger

𝐵𝑇&𝐵𝐾&𝑆𝑎𝑛𝑑𝑤𝑖𝑐ℎ𝑉𝑒𝑡𝑜• Thiswillprovideanexpectedrateof25kHz

Upstream Threshold Cherenkov counter

BeamandTriggererror~0.5%


LostInteractionevents• Selectafiducialvolumeonthetarget[-68,-30]cm• Lookhowmanyeventshaveareconstructedvertexwithinthefiducialvolume

MCevents:288312NoVertex:2753(0.95%)Vtx outside:2856(0.99%)

ThankstotheRecoilDetectorno-vertexeventscanbecross-

checkedwithdata

Vertex error 0.5%


Summaryoftheexpectederrors


efficiency est syserror

TrackRecon 95% ~1%

Rich Efficiency ~99% ~0.5%

RICH PID 99 to75% 0.1to4%

Trigger 1%

Vertex error 98% 0.5%

BeamPurity 99.9% 0.5%

TOTAL 4to6%

Considering2targets(LHe andLH2,each50cmlong),TheestimatedacceptanceandefficiencyfromthefullCOMPASSMC.20binsinmomentumfrom[10,50]GeV/cand20bininPt75%beampurityat5E5p/sbeamintensityWeexpecttoreach1.7(1.0)%statistical errorinmostofthe400differentialcrosssectionbinswith4(12)hoursofbeamtimeforeachenergypoint.

Systematic

Towardanactualmeasurement


Theprogramformeasuringp-pandp-He->pbar (anddbar)+XhasbeenincludedintheCOMPASS2020LoI presentedtoCERN

ThenewprogramhasbeennamedCOMPASS++_AMBER.

TheprogramwouldstartaftertheLHClongshutdownin2021.Preliminarymeasurementsareexpectedtobeperformedin2021and2022.

TheLoI receivedapositiveevaluationandthecollaborationhasbeenrequestedtoprepareaproposalwithinthesummer

ProjectstoconvertaspareLH2targettoLHe willalsostartsoverthesummer.

Summary

• CRantimatterdatasensitivitytoexoticsourcesisdegradedbythepoorknowledgeofthepbar (anddbar)productioncrosssections

• Wehaveshownthatameasurementofp-p->pbar +Xandp-He->pbar +X(anddbar),canbeperformedatCERNwiththeCOMPASS++/AMBERspectrometeratmomentarangingfrom50GeV/cto280GeV/c

• Aletterofintentthatincludesaprogramforthesemeasurementshasbeensubmittedandreceivedapositiveevaluation

• Afullproposalisbeingnowworked

• Firstdatatakingissupposedtohappenin2021


Particlerangeat50GeV/cmomentum


MC_PID Name range Mass Charge Lifetime Energy Beta gammam GeV/c2 s GeV

20SIGMA0 9.31E-10 1.19E+00 0 7.40E-20 5.00E+01 1.00E+00 4228ANTISIGMA0 9.31E-10 1.19E+00 0 7.40E-20 5.00E+01 1.00E+00 4217ETA 1.50E-08 5.48E-01 0 5.49E-19 5.00E+01 1.00E+00 917PION0 9.33E-06 1.35E-01 0 8.40E-17 5.00E+01 1.00E+00 37024OMEGA- 7.38E-01 1.67E+00 -1 8.22E-11 5.00E+01 9.99E-01 3032ANTIOMEGA+ 7.38E-01 1.67E+00 1 8.22E-11 5.00E+01 9.99E-01 3027ANTISIGMA- 1.01E+00 1.19E+00 -1 7.99E-11 5.00E+01 1.00E+00 4219SIGMA+ 1.01E+00 1.19E+00 1 7.99E-11 5.00E+01 1.00E+00 4221SIGMA- 1.85E+00 1.20E+00 -1 1.48E-10 5.00E+01 1.00E+00 4229ANTISIGMA+ 1.85E+00 1.20E+00 1 1.48E-10 5.00E+01 1.00E+00 4223XI- 1.86E+00 1.32E+00 -1 1.64E-10 5.00E+01 1.00E+00 3831ANTIXI+ 1.86E+00 1.32E+00 1 1.64E-10 5.00E+01 1.00E+00 3816KAON0SHORT 2.69E+00 4.98E-01 0 8.93E-11 5.00E+01 1.00E+00 10022XI0 3.31E+00 1.32E+00 0 2.90E-10 5.00E+01 1.00E+00 3830ANTIXI0 3.31E+00 1.32E+00 0 2.90E-10 5.00E+01 1.00E+00 3818LAMBDA 3.54E+00 1.12E+00 0 2.63E-10 5.00E+01 1.00E+00 4526ANTILAMBDA 3.54E+00 1.12E+00 0 2.63E-10 5.00E+01 1.00E+00 4512KAON- 3.76E+02 4.94E-01 -1 1.24E-08 5.00E+01 1.00E+00 10111KAON+ 3.76E+02 4.94E-01 1 1.24E-08 5.00E+01 1.00E+00 10110KAON0LONG 1.56E+03 4.98E-01 0 5.17E-08 5.00E+01 1.00E+00 1009PION- 2.80E+03 1.40E-01 -1 2.60E-08 5.00E+01 1.00E+00 3588PION+ 2.80E+03 1.40E-01 1 2.60E-08 5.00E+01 1.00E+00 3586MUON- 3.12E+05 1.06E-01 -1 2.20E-06 5.00E+01 1.00E+00 4735MUON+ 3.12E+05 1.06E-01 1 2.20E-06 5.00E+01 1.00E+00 47313NEUTRON 1.42E+13 9.40E-01 0 8.87E+02 5.00E+01 1.00E+00 5325ANTINEUTRON 1.42E+13 9.40E-01 0 8.87E+02 5.00E+01 1.00E+00 5346TRITON 5.35E+24 2.81E+00 1 1.00E+15 5.01E+01 9.98E-01 1845DEUTERON 8.00E+24 1.88E+00 1 1.00E+15 5.00E+01 9.99E-01 2715ANTIPROTON 1.60E+25 9.38E-01 -1 1.00E+15 5.00E+01 1.00E+00 5314PROTON 1.60E+25 9.38E-01 1 1.00E+15 5.00E+01 1.00E+00 533ELECTRON 2.94E+28 5.11E-04 -1 1.00E+15 5.00E+01 1.00E+00 978472POSITRON 2.94E+28 5.11E-04 1 1.00E+15 5.00E+01 1.00E+00 9784749HE3 5.35E+24 2.81E+00 2 1.00E+15 5.01E+01 9.98E-01 1847ALPHA 4.04E+24 3.73E+00 2 1.00E+15 5.01E+01 9.97E-01 13

production cross sections for anti-p and anti-d with ... · production cross sections for anti-p...

Documents