TakumiYamagaResearchCenterforNuclearPhysics,Osakauniversity

FortheJ-PARCE15collabora<on

Interna<onalNuclearPhysicsConference2016   September11-16,2016@Adelaide

September15,2016

Improved^↑𝟑↓𝐇𝐞 (𝑲↑− ,𝚲𝒑)𝒏Spectroscopy

toSearchforthe 𝑲 𝑵𝑵BoundStatewithJ-PARCE15-2ndData

T.Yamaga

Contentsu Introduc<onofKNNboundstate

u E15Experiment

u ResultsofE15-2nd

u Summary

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T.Yamaga

KbarNInterac<onandKaonicNucleiu KbarNinterac<on

►  On/Abovethreshold•  Wellstudied

»  Low-energyscaUering

»  X-rayfromKaonicatoms

•  Kbar–Nucleon»  AUrac<veinI=0

•  Kbar–Nucleus»  AUrac<ve

►  Subthreshold•  Notwellunderstood

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u Boundstateof 𝑲 –Nucleus?► Kaonicnucleus

•  ConsistofBaryonandMeson•  Deeplybound•  Highdensity

Informa<onofKbarNinterac<oninsubthresholdregion

Startwiththe“simplest”KbarNNsystem

T.Yamaga

Situa<onof𝑲↑− 𝒑𝒑boundstate

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E-dep.

E-indep.

Reportsstructure �J-PARCE27𝑑(𝜋↑+ , 𝐾↑+ )𝑋DISTO𝑝𝑝→Λ𝑝𝐾↑+ 

FINUDA(𝑠𝑡𝑜𝑝𝑝𝑒𝑑 𝐾↑− ,Λ𝑝)

/NOstructure �

HADES𝑝𝑝→Λ𝑝𝐾↑+ 

LEPS𝑝(𝛾, 𝜋↑− 𝐾↑+ )𝑋

► Experiments

► Theore<calcalc.BoundstateexistsKbarNinterac<onmodelE-dep./E-indep.

T.Yamaga

J-PARCE15Experimentu Searchingfor𝑲↑− 𝒑𝒑

► (𝑲↑− , 𝒏)reac<on@1GeV/c

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𝑲↑−  ^↑𝟑↓𝐇𝐞 

" 𝑲↑− 𝒑𝒑"

𝝅↑− 

𝒑

𝒑𝚲

𝒏𝒏" 𝑲↑− 𝒑𝒑"

Beamsweepingmagnet

Neutroncounter

CDS

Beamspectrometer

T.Yamaga

u 𝚲𝒑invariantmassspectroscopyin^↑𝟑↓𝐇𝐞 (𝑲↑− , 𝚲𝒑)"𝒏“ reac<on

J-PARCE15Experiment

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^↑𝟑↓𝑯𝒆 ( 𝑲↑− , 𝜦𝒑)"𝑿"Missing-mass �

“𝒏””

► 𝝅𝒑𝒑eventselec<oninCDS

► 𝚲→𝝅↑− 𝒑-pairselec<on•  Likelihoodmethod

► Missingneutronselec<on•  𝟎.𝟖𝟓 −𝟏.𝟎𝟑 𝐆𝐞𝐕/ 𝒄↑𝟐 

T.Yamaga

E15-1stResult

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Y. Sada, et al, Prog. Theor. Exp. Phys. (2016) 051D01

► E15-2ndexperiment» ×𝟑𝟎𝜦𝒑𝒏events𝜦𝒑𝒏eventsevents

►  E15-1stexperiment•  𝚲𝒑invariantmassanalysisin^↑𝟑↓𝐇𝐞( 𝑲↑− ,𝚲𝒑)"𝒏" 

•  AssumingsimpleBreit-Wigner»  B.E.:𝟏𝟓 𝐌𝐞𝐕,Width:𝟏𝟏𝟎 𝐌𝐞𝐕

IncreasingSta<s<cs �

𝑴↓𝑲↑− 𝒑𝒑 

𝑴↓𝝅

𝚺𝒑 

T.Yamaga

E15-2ndResult

u  ConsistentwiththeE15-1stresult

u  Structurearound𝑴↓𝑲↑− 𝒑𝒑↑ 

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𝒏↓𝒘𝒊𝒏𝒅𝒐𝒘 =𝟎.𝟖𝟓 −𝟏.𝟎𝟑 𝑮𝒆𝑽/ 𝒄↑𝟐 

𝑴↓𝑲↑− 𝒑𝒑 

𝑴↓𝝅

𝚺𝒑 

► E15-2ndexperiment» ×𝟑𝟎𝜦𝒑𝒏events𝜦𝒑𝒏eventsevents

T.Yamaga

𝑰𝑴(𝚲𝒑)vs.𝐜𝐨𝐬𝜽↓𝒏↑ ↑𝑪𝑴  Plotu Neutronopeningangle

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𝑴↓𝑲↑− 𝒑𝒑 

𝑰𝑴(𝚲𝒑)vs.𝐜𝐨𝐬𝜽↓𝒏↑ ↑𝑪𝑴  

CMframe

Beam

𝑝

Λ

"𝑛"

𝜃↓𝑛↑𝐶𝑀 

Outofacceptance �

Forwardangle �

T.Yamaga

𝐜𝐨𝐬𝜽↓𝒏↑ ↑𝑪𝑴  Sliced𝑰𝑴(𝚲𝒑)

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u 𝟎.𝟕𝟓< cos𝜽↓𝒏↑𝑪𝑴  <𝟏.𝟎𝟎

𝑴↓𝑲↑− 𝒑𝒑 

2peaks+3NA�

u 𝟎.𝟎𝟎< cos𝜽↓𝒏↑𝑪𝑴  <𝟎.𝟕𝟓

2peaks+3NA�

u 𝟎.𝟎𝟎< cos𝜽↓𝒏↑𝑪𝑴  <𝟏.𝟎𝟎

2peaks+3NA �

Outofacceptance �

T.Yamaga

𝐜𝐨𝐬𝜽↓𝒏↑ ↑𝑪𝑴  Sliced𝑰𝑴(𝚲𝒑)

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𝑴↓𝝅

𝚺𝐩 

2peaksobserved �Abovethreshold �► Quasi-elas<cprocess

Belowthreshold �► Couldbe 𝑲↑− 𝒑𝒑𝑴

↓𝑲↑− 𝒑𝒑 

𝑴↓𝝅

𝚺𝐩 

𝑴↓𝑲↑− 𝒑𝒑 

E-dep.E-indep.

Thiswork �

T.Yamaga

SummarySummary

areobserved.► Locatedintheforwardregion(𝐜𝐨𝐬𝜽↓𝒏↑𝑪𝑴 >𝟎.𝟕𝟓 )► Peakbelowthresholdcouldbe 𝑲↑− 𝒑𝒑state.

u Detailedanalysisisongoing.Detailedanalysisisongoing.2016.09.152016.09.15

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2016.09.15 INPC2016@Adelaide

∼TheE15collabora<on∼ThankyouforyouraUen<on

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