PREX and CREX 208. Neutron Skin. Robert Michaels Jefferson Lab APS 2017

Transcription

1 PREX an CREX 08 Pb R L A ~ 10 ~ 10 PV Q e 0 R L Hoowitz 48 Ca e Z Robet Michaels Jeffeson Lab APS 017 Electoweak Asymmety in Elastic Electon-Nucleus Scatteing : A measue of the neuton istibution Neuton Skin R n R p n p 1/15

2 PREX Kent Paschke * UVa Kishna Kuma Stony Book Univesity Robet Michaels Jeffeson Lab Seamus Rioan* Robet Michaels Kent Paschke Paul Soue CREX Stony Book Univesity Jeffeson Lab UVa Syacuse Univeisty Paul Soue Syacuse Univeisty Dustin McNulty Iaho State Univesity Guio Ucioli INFN Rome Juliette Mammei Manitoba Univesity * contact pesons Silviu Covig Jeffeson Lab Neuton Skin of 08 Pb an 48 Ca Jan 18, 017 p / 9

3 Neuton fom facto A G F Q 1 4sin W F F N P ( Q ( Q Choice of Nuclea Tagets Fist excite state fa fom elastic Neuton excess Doubly-magic Stable Hall A 08 Pb 48 Ca Robet Michaels, APS 017 Hall A High Resolution ( 10-4 Spectometes

4 Neuton Skin vs Mass Numbe A R N R P (fm C-REX Appove poposal PREX-I publishe PREX-II Appove poposal Theoy : P. Ring et al. NPA 64, 349 (1997 A Robet Michaels, APS 017 p4 / 9

5 ( ( ˆ( 5 A V V ( ( 4sin 1 Q F Q F Q G A P N W F L R L R neuton weak chage >> poton weak chage is small, best obseve by paity violation ( ( / / / 3 Z V ( ( 4sin (1 ( N Z G A N P W F ( Q F P Mott ( ( 4 1 ( 0 3 q j Q F P P ( ( 4 1 ( 0 3 q j Q F N N Electon - Nucleus Potential electomagnetic axial Neuton fom facto Paity Violating Asymmety A( 1 4sin 1 W Poton fom facto 0 Pb is spin 0 08 Using Paity Violation p5 / 9 Robet Michaels, APS 017

6 Weak Inteaction: Sees the Neutons poton neuton Electic chage 1 0 Weak chage Measue Asymmety Coect fo Coulomb Distotions APPLICATIONS Nuclea Theoy (Symmety Enegy Weak Density at one Q Small Coections fo n s G E G E MEC suface thickness Heavy Neuton Atomic Paity Violation Skin Ions Stas R N - R P

7 Ways to Fin Neuton Distibution an Symmety Enegy Poton-Nucleus Elastic Pion, alpha, Scatteing Pion Photopouction Heavy ion collisions Rae Isotopes (ipline Electic Dipole Polaizabilities Magnetic scatteing Involve stong pobes Most spins couple to zeo. PREX / C-REX A PV ( weak inteaction Theoy MFT fit mostly by ata othe than neuton ensities Robet Michaels, APS 017 p7 / 9

8 Neuton skin measue by APV Robust coelation between 08 Pb APV an the neuton skin ove existing nuclea stuctue moels X. Roca-Maza (et al. PRL 106 ( Apv in PVES povies a clean pobe of the neuton istibution PREX: APV to 3% fom 08 Pb CREX: APV to.5% fom 48 Ca -> n to 0.06 fm -> n to 0.0 fm Robet Michaels, APS 017 Neuton Skin of 08 Pb an 48 Ca Jan 18, 017 p8 / 9 8

9 Neuton skin an Symmety Enegy Mean-Fiel peictions show a coelation between neuton skin of a heavy nucleus an the ensity slope of the symmety enegy. Slope of symmety enegy at satuation ensity X. Roca-Maza (et al. PRL 106 ( n calibates the Equation of State of neuton ich matte, etemining L Neuton Skin of 08 Pb an 48 Ca Jan 18, 017 p9 / 9 9

10 Ab Initio (exact micoscopic calculations of R skin fo 48 Ca have ecently been publishe. G. Hagen et al., Natue Physics 1, 186 (016. Can be compae to Density Functional Theoy (the e an blue points an Dispesive Optical Moel (DOM. W. Dickhoff [nucl-th] Fattoyev, Piekaewicz PRC 86, (01 G. Hagen, et al. Natue 1, 186 (015 Robet Michaels, APS 017

11 Danielewicz, Lacey, an Lynch, Science 98 ( Connecting low to meium to high ensity neutons Low ensity : nuclei Meium ensity : Heavy Ion Collisions Highest ensity : Neuton Stas Dany Page Robet Michaels, APS / 9

12 elationship to Neuton Stas Input : Eq. of state (EOS P( PREX / CREX helps hee Deuce Mass-Raius elationship, an othe popeties Cab Pulsa Neuton skin is highly coelate with seveal neuton sta popeties J. Piekaewicz, Rev. Nuc. Phys 10 ( p1 / 9

13 Paity Expeiment Metho (integating moe Flux Integation Technique: C-REX : 140 MHz PREX: 500 MHz Example : HAPPEX

14 Paity Violating Asymmety A PV R R L L ~ 10 4 Q ~ 10 6 e Pb e Z 08 Pb A PV fom intefeence Applications of A PV at Jeffeson Lab Nucleon Stuctue Stangeness s s in poton (HAPPEX, G0 expts Test of Stana Moel of Electoweak e e (MOLLER o e q (PVDIS elastic e p at low Q (QWEAK sin Nuclea Stuctue (neuton ensity : PREX W & CREX Robet Michaels, APS 017 p 14 / 9

15 Hall A High Resolution Spectometes Resolve Elastic Scatteing Disciminate Excite States Elastic Inelastic etecto taget Quas Dipole Qua Quatz etectos scintillato Dift chambes Robet Michaels, APS 017 p 15 / 9

16 Spectometes at Jeffeson Lab Hall A Robet Michaels, APS 017

17 HRS + septum Pb taget PREX-I Results PRL 108 ( A Physics Asymmety ppm 0.060( stat 0.014( syst Hall A JLAB Pol. Souce CEBAF Statistics limite ( 9% Systematic eo goal achieve! (% Septum Magnet HRS Pb taget / 9

18 Units: micons Paity Quality Beam : Unique Stength of JLab Helicity Coelate Position Diffeences X R X L fo helicity L, R Plotte below Points: Not sign-coecte nm iffs. with pol. souce setup & feeback Sign flips povie futhe suppession : Aveage with signs = what expeiment feels achieve < 5 nm A aw = A et - A Q + E + i x i Sign flips using ½ wave plate & Wien filte This BPM, Aveage =.4 PREX ata Measue sepaately 3.1 nm Slug # ( ~ 1 ay 18 / 9

19 PREX-I Asymmety (P e x A ppm Slug ~ 1 ay Robet Michaels, APS / 9

20 Asymmety leas to R N PREX-I has establishe a neuton skin at ~95 % CL Neuton Skin = R N - R P = fm PRL 108 ( Robet Michaels, APS 017

21 PREX-II an C-REX Status Impove the shieling an vacuum seals Both expeiments appove PREX-II A ating 35 ays C-REX A- ating 45 ays Systematic Eo Goals fo PREX-II emonstate by PREX-I spectometes tagets 08 Pb 48 Ca Robet Michaels, APS 017 p 1 / 9

22 PREX / CREX PREX-I E=1.1 GeV, 5 o A=0.6 ppm Chage Nomalization 0.% Beam Asymmeties 1.1% Detecto Non-lineaity 1.% Tansvese Asym 0.% Polaization 1.3% Taget Backing 0.4% Inelastic Contibution <0.1% Effective Q 0.5% Total Systematic.1% Total Statistical 9% Achieve, publishe statistics limite esult, systematics well une contol PREX-: 3% stat, 0.06 fm CREX:.4% stat, 0.0fm PREX-II E=1.1 GeV, 5 o A=0.6 ppm 70 μa, 5+10 ays Chage Nomalization 0.1% Beam Asymmeties* 1.1% Detecto Non-lineaity* 1.0% Tansvese Asym 0.% Polaization* 1.1% Taget Backing 0.4% Inelastic Contibution <0.1% Effective Q 0.4% Total Systematic % Total Statistical 3% *Expeience suggests that leaing systematic eos can be impove beyon poposal Expeiments CREX E=1.9 GeV, 5 o A =.3 ppm 150 μa, ays Chage Nomalization 0.1% Beam Asymmeties 0.3% Detecto Non-lineaity 0.3% Tansvese Asym 0.1% Polaization 0.8% Taget Contamination 0.% Inelastic Contibution 0.% Effective Q 0.8% Total Systematic 1.% Total Statistical.4% Robet Michaels, APS 017 p Neuton / 9 Skin of 08 Pb an 48 Ca Jan 18, 017

23 PREXI emonstate technologies fo PREXII What Woke: New Septum Reaches smalle angles than HRS, which impoves the FOM HRS Tune PREX-I taught us how to tune the HRS optimize fo ou small etectos. Polaimety at low enegy High-fiel Molle at 1.3%, Integating Compton at 1.% New Detectos Suitable enegy esolution achieve fo 1 GeV electons. <5% pecision loss. Lea Taget Establishe Min Suvival lifetime >5 C exposue Neee to esolve: Taget Vacuum system Raiation in Hall Fast Helicity Flipping We know how to contol false asymmeties an monito pefomance Injecto Spin Manipulation Secon Wein an solenoi ae calibate an use fo helicity evesal. Impotant cancellation fo systematic beam asymmeties fom the polaize souce. Beam Moulation System Fast beam kicks cancel low fequency noise an impove pecision of beam position coections AT false asymmety AT is small (<1 ppm Pb, <10 ppm C an Afalse will be small if PT is minimize Reay to meet PREX-II/CREX systematic an statistical goals Neuton Skin of 08 Pb an 48 Ca Jan 18, / 9 3

24 New PREX / CREX Scatteing Chambe One cyo-coole pouction taget lae an one calibation-taget lae. Impove (ha vacuum seals Run PREX an CREX with one installation Small chambe allows efficient shieling Beam Septum magnet Collimato Box Scatteing Chambe Beam Robet Michaels, APS 017 Neuton Skin of 08 Pb an 48 4 / 9 Ca Jan 18, 017 4

25 Impove Raiation Shieling PREX-I istibute significant powe in the hall, amaging electonics Solution: Localize powe in hall at collimato, an shiel it Powe in collimato (W/μA Powe in hall (W/μA Taget lea PREX-I PREX-II CREX ~1.5 beam collimato poly tungsten 1 MeV neuton-equivalent integate ose HRS PS platfom PREX- (1 MeV-n / cm PREX- /PREX PREX- /HAPPEX- electons 1.4E+10 11% 70% neutons 7.6E+09 7% 94% total.1e+10 9% 83% septum 1 MeV-neq/cm is below expecte electonics amage theshol ( PREX- ose will be compaable to othe Hall A expeiments like HAPPEX- Neuton Skin of 08 Pb an 48 Ca Jan 18, 017 5

26 Detectos Developments GEMs PMT Cheenkov aiation fom electons tavesing thin quatz. Quatz etectos Electons in HRS Quatz etecto e - Simulation an ata benchmake quatz popeties Also, GEMs fo high-ate tacking Teste at Iaho an Stony Book Beam tests at Mainz RMS/Mean ~ 19% Neuton Skin of 08 Pb an 48 Ca Jan 18, 017

27 Beam afte 1 GeV Upgae Tests uing ecent paasitic beam stuies to check beam quality, monitos BCM esolution excees PREX equiements PREX-II statistical with ~ 30Hz octet/quatet BCM esolution of 40ppm woul be 5% loss of esolution BCM electonics: 5 ppm 30 Hz, 0uA Confime by excess noise with small-angle monitos ouble-iffeence with Resolution < 30 ppm Chage an position jitte AQ: ppm RMS. Δx: 5-5 um RMS. (0 μa, 30 Hz,. GeV 1 pass beam 4 pass beam X, Y The beam is goo enough to o the expeiments. Neuton Skin of 08 Pb an 48 Ca Jan 18, 017 7

28 Futue Weak Chage Scan? Electon Scatteing lowe Q at Mainz highe Q at JLab Focusing Solenoi M. Thiel, D. Becke, P. Soue Z. Lin, S. Ban, C.J. Hoowitz J. Phys. G ; PRC C9, Robet Michaels, APS 017 p 8 / 9

29 PREX, C-REX : Summay Funamental Nuclea Physics with many applications PREX-I : 9% stat. eo in Asymmety Goals: PREX-II 3 % 0.06 fm, C-REX.4% 0.0 fm Systematic Eo Goals Achieve Poblems being fixe: shieling an a-ha vacuum seals. PREX-II & C-REX possibly to un in 018 Robet Michaels, APS 017