R e c e n t r e s u l t s a n d p r o s p e c - PowerPoint PPT Presentation

R e c e n t r e s u l t s a n d p r o s p e c t s f r o m t h e N A 6 2 e x p e r i m e n t a t C E R N K a r i m Ma s s r i – C E R N ( e m a i l : k a r i m . m a s s r i @ c e r n . c h ) P a r t i c l e p h y s i c s s e m i n a r – B i r m i n g h a m – 1 2 / 0 2 / 2 0 2 0

The K + → p + nn decay + → p + K nn : Mo t i v a t i o n s & T h e o r y h i g h s e n s i t i v i t y ● F C N C f o r b i d d e n a t t r e e l e v e l : 1 - l o o p c o n t r i b u t i o n s a s l e a d i n g o r d e r t o n e w p h y s i c s + + * 2 λ 1 0 ● H i g h l y C K M s u p p r e s s e d : B R ( K →π ν ν ) ~ | V V | ~ t s t d ● D o m i n a t e d b y s h o r t - d i s t a n c e c o n t r i b u t i o n ( t o p q u a r k ) ● t q u a r k c o n t r i b u t i o n @ N L O Q C D a n d 2 - l o o p E W c o r r e c t i o n s , h i g h - p r e c i s i o n c q u a r k @ N N L O Q C D a n d 1 - l o o p E W c o r r e c t i o n s t h e o r e t i c a l p r e d i c t i o n ± ± 0 • H a d r o n i c m a t r i x e l e m e n t f r o m B R ( K →e π ν ) ● Me a s u r e m e n t o f | V | c o m p l e m e n t a r y S M p r e d i c t i o n : t d + → p + nn ) – 1 0 B R ( K = ( 0 . 8 4 ± 0 . 1 0 ) × 1 0 0 t o t h o s e f r o m B − B m i x i n g o r B → ρ γ B u r a s e t a l . , J H E P 1 5 1 1 ( 2 0 1 5 ) 0 3 3 . ● C o n s t r a i n t s o n C K M u n i t a r y t r i a n g l e 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 2

The K + → p + nn decay + → p + K nn : N e w P h y s i c s s c e n a r i o s ● C u s t o d i a l R a n d a l l - S u n d r u m [ B l a n k e e t a l . , J H E P 0 9 0 3 ( 2 0 0 9 ) 1 0 8 ] ● MS S M a n a l y e s [ B l a z e k a n d Ma t a k , I n t . J . Mo d . P h y s . A 2 9 ( 2 0 1 4 ) 1 4 5 0 1 6 2 ] [ I s i d o r i e t a l . , J H E P 0 6 0 8 ( 2 0 0 6 ) 0 6 4 ] ● S i m p l i fj e d Z , Z ' m o d e l s [ B u r a s , B u t t a z z o , K n e g j e n s , J H E P 1 5 1 1 ( 2 0 1 5 ) 1 6 6 ] ● L i t t l e s t H i g g s w i t h T - P a r i t y [ B l a n k e e t a l . , E P J C 7 6 ( 2 0 1 6 ) 1 8 2 ] ● L F U v i o l a t i o n m o d e l s [ I s i d o r i e t a l . , E P J C 7 7 ( 2 0 1 7 ) 6 1 8 ] ● C o n s t r a i n t s f r o m e x i s t i n g m e a s u r e m e n t s ( c o r r e l a t i o n s m o d e l d e p e n d e n t ) K a o n m i x i n g , C K M e l e m e n t s , K , B r a r e m e s o n d e c a y s , N P l i m i t s f r o m d i r e c t s e a r c h e s R a n d a l l - S u n d r u m Z ' ( 5 T e V ) i n C o n s t r a i n e d M F V L F U v i o l a t i o n 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 3

The K + → p + nn decay + → p + K nn : E x p e r i m e n t a l R e s u l t s D e c a y - a t - r e s t t e c h n i q u e D e c a y - i n - fm i g h t t e c h n i q u e N A 6 2 ( 2 0 1 6 d a t a ) B R ( K + → p + nn ) < 1 4 × 1 0 – 1 0 @ 9 5 % C L B R ( K + → p + nn ) = ( 1 . 7 3 + 1 . 1 5 ) × 1 0 – 1 0 – 1 . 0 5 N A 6 2 , P h y s . L e t t . B 7 9 1 ( 2 0 1 9 ) 1 5 6 E 7 8 7 / E 9 4 9 , P R L 1 0 1 ( 2 0 0 8 ) 1 9 1 8 0 2 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 4

The NA62 experiment T h e N A 6 2 e x p e r i m e n t @ C E R N N A 6 2 i s t h e l a s t f r o m a l o n g t r a d i t i o n o f fj x e d - t a r g e t K a o n e x p e r i m e n t s i n t h e C E R N N o r t h A r e a History of NA48/NA62 experiments 1997 Re ε′/ε ¯ Discovery of NA48 (K S /K L ) 2001 direct CPV NA48/1 Rare K S and (K S /hyperons) 2002 hyperon decays 2003 Direct CPV, ¯ Rare K + /K - NA48/2 (K + /K – ) 2004 decays 2007 R K = K ± e2 /K ± m 2, ¯ NA62-R K (K + /K – ) Rare K + /K – 2008 decays 2016 K + → p + nn , ¯ Rare K + and p 0 NA62 (K + ) - decays N A 6 2 : c u r r e n t l y ~ 2 0 0 p a r t i c i p a n t s , 2 9 i n s t i t u t i o n s f r o m 1 2 c o u n t r i e s 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 5

The NA62 experiment + → p + K nn i n N A 6 2 : s t r a t e g y + → p + nn K s i g n a t u r e : K a o n t r a c k + P i o n t r a c k + N O T H I N G E L S E N A 6 2 K e y s t o n e s : – P r e c i s e t r a c k i n g – P a r t i c l e I D ( i n p a r t i c u l a r p / m ) – P h o t o n r e j e c t i o n – P r e c i s e t i m i n g ~ O ( 1 0 0 p s ) B a c k g r o u n d r e j e c t i o n a t ~ 1 0 1 1 l e v e l 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 6

The NA62 experiment T h e N A 6 2 b e a m a n d d e t e c t o r 4 0 0 G e V / c p r i m a r y S P S p r o t o n s 1 2 ( ~ 2 ´ 1 0 / s p i l l ) S e c o n d a r y h a d r o n b e a m : D e c a y r e g i o n : ● + p + ● 6 0 m l o n g fj d u c i a l v o l u m e C o m p o s i t i o n : K ( 6 % ) / ( 7 0 % ) / p ( 2 4 % ) – 6 ● p = 7 5 G e V / c , D p / p ~ 1 % ● V a c u u m ~ O ( 1 0 m b a r ) + ● 1 0 0 m r a d d i v e r g e n c e ( R MS ) ● ~ 5 MH z K d e c a y r a t e ´ 2 ● 6 0 3 0 m m t r a n s v e r s e s i z e ● I n t e n s i t y : 7 5 0 MH z ( 4 5 MH z K + ) 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 7

The NA62 experiment T h e N A 6 2 b e a m a n d d e t e c t o r . . . a n d t h i s i s h o w i t r e a l l y l o o k s ! 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 8

Search for the K + → p + nn decay T h e 2 0 1 6 – 2 0 1 8 D a t a S a m p l e F u l l 2 0 1 6 - 2 0 1 8 s a m p l e : 1 2 ~ 5 ´ 1 0 k a o n d e c a y s , ~ 3 P B o f r a w d a t a o n d i s k O ( 1 0 ) t r i g g e r s t r e a m s , b r o a d p h y s i c s r e a c h 1 0 0 % n o m i n a l i n t e n s i t y [ = 7 5 0 MH z h a d r o n b e a m ] T r i g g e r m a s k D o w n s c a l e pnn 1 2m 2 e , m u l t i - t r a c k 8 ~ 5 5 % n o m i n a l m , m u l t i - t r a c k 1 0 i n t e n s i t y Mu l t i - t r a c k 5 0 - 1 0 0 N o n - m 2 0 0 ~ 6 5 % n o m i n a l ~ 4 0 % Mi n i m u m b i a s 4 0 0 i n t e n s i t y . . . 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 9

K + → p + nn selection S i g n a l s e l e c t i o n + K d e c a y s i n t h e fj d u c i a l v o l u m e , M i n i m u m b i a s t r i g g e r S e l e c t i o n c r i t e r i a : K + → p + p + p – ● S i n g l e t r a c k t o p o l o g y 2 4 m p + p + ● i d e n t i fj c a t i o n ● P h o t o n r e j e c t i o n K + → p + p 0 R e g i o n I I ● Mu l t i - t r a c k r e j e c t i o n K + → m + n 2 m p 0 R e g i o n I A n a l y s i s s t r a t e g y : S i g n a l a n d C o n t r o l R e g i o n s k e p t b l i n d t h r o u g h o u t t h e a n a l y s i s 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 10

Search for the K + → p + nn decay N A 6 2 K e y s t o n e 1 : P r e c i s e t r a c k i n g 2 m r e s o l u t i o n : m i s s 2 – 3 2 4 s ( m ) = 1 0 G e V / c m i s s D e s i g n v a l u e ! 12/02/2020 Karim Massri – Particle physics seminar – Birmingham 11