A t r i B h a t t a c h a r y a T a l k a t I - PowerPoint PPT Presentation

D D e e t t e e c c t t i i n n g g T T e e V V - - P P e e V V s s c c a a l l e e d d a a r r k k ma ma t t t t e e r r s s i i g g n n a a t t u u r r e e s s a a t t D D e e t t e e c c t t i i n n g g T T e e V V - - P P e e V V s s c c a a l l e e d d a a r r k k ma ma t t t t e e r r s s i i g g n n a a t t u u r r e e s s a a t t t t h h e e I I c c e e C C u u b b e e n n e e u u t t r r i i n n o o d d e e t t e e c c t t o o r r t t h h e e I I c c e e C C u u b b e e n n e e u u t t r r i i n n o o d d e e t t e e c c t t o o r r A t r i B h a t t a c h a r y a T a l k a t I n s t i t u t e O f P h y s i c s , B h u b a n e s wa r 0 4 A u g u s t 2 0 1 4

P l a n P l a n  U l t r a - H i g h E n e r g i e s a n d t h e I c e C u b e n e u t r i n o d e t e c t o r – T h e I C s e t u p , a i ms a n d o b j e c t i v e s – R e c e n t r e s u l t s a t I C – I s s u e s wi t h s t a n d a r d e x p l a n a t i o n s  D a r k M a t t e r d e c a y a n d n e u t r i n o s a t I C  Di r e c t s e a r c h f o r h e a v y DM a t I C  Ge n e r a l p r o s p e c t s f o r h e a v y DM s e a r c h e s

T h e n e u t r i n o s k y . . . t o t h e h i g h e s t e n e r g i e s T h e n e u t r i n o s k y . . . t o t h e h i g h e s t e n e r g i e s

T h e n e u t r i n o s k y . . . t o t h e h i g h e s t e n e r g i e s T h e n e u t r i n o s k y . . . t o t h e h i g h e s t e n e r g i e s Probe highest Probe neutrino energy neutrino oscillation at production highest energies mechanisms Existence of tiny DM annihilation non-std physical at the effects (LV, etc.) galactic centre Hunting for astrophysical Indirect search point objects for very heavy (AGN, etc.) using DM decay neutrinos

T h e n e u t r i n o s k y . . . t o t h e h i g h e s t e n e r g i e s T h e n e u t r i n o s k y . . . t o t h e h i g h e s t e n e r g i e s Probe highest Probe neutrino energy neutrino oscillation at production highest energies mechanisms Existence of tiny DM annihilation non-std physical at the effects (LV, etc.) galactic centre Hunting for astrophysical Indirect search point objects for very heavy (AGN, etc.) using DM decay neutrinos

N e u t r i n o s @ h i g h e s t e n e r g i e s : H o w C a t c h ' e m N e u t r i n o s @ h i g h e s t e n e r g i e s : H o w C a t c h ' e m Ma i n i s s u e s wi t h d e t e c t i o n ● E x t r e me l y l o w i n c i d e n t fm u x e s ● Hu g e i n c i d e n t e n e r g i e s – r e c o n s t r u c t i o n r e q u i r e s v o l u mi n o u s d e t e c t o r s ● F l a v o u r d i s c r i mi n a t i o n ? S o l u t i o n ? K m 3 D e t e c t o r s K m 3 d e t e c t o r s m 3 K d e t e c t o r s ● Trap high fraction of incident neutrino fluxes ● Proper energy and direction (for tracks) reconstruction of large event signature tracks ● Big enough to contain hadronic/em cascades ● Possibility of detection of double-bang signatures from incident ν τ 's

ν ν P r e s e n t s e t u p f o r U H E d e t e c t i o n P r e s e n t s e t u p f o r U H E d e t e c t i o n I c e C u b e  Op e r a t i o n a l s i n c e 2 0 1 0 – F u l l e x p o s u r e s i n c e De c . 2 0 1 1  C a p a b l e o f fm a v o u r d i s c r i mi n a t i o n – L i mi t e d t o d e t e c t i o n o f t h r e e d i s t i n c t e v e n t s i g n a t u r e s  E x c e l l e n t e n e r g y r e c o n s t r u c t i o n – < 1 0 % f o r c o n t a i n e d c a s c a d e s – ~ 3 0 % f o r t r a c k s wi t h c o n t a i n e d v e r t i c e s  Go o d d i r e c t i o n r e c o n s t r u c t i o n – U p t o 1 ° f o r t r a c k s – ~ 3 0 ° f o r c a s c a d e s  De s i g n e d t o r u n ( mi n i ma l o p . c o s t ) f o r 1 0 + y r s  2 8 UHE e v e n t s i n 6 6 2 d a y s o f r u n - t i me – 2 e v e n t s a t P e V + e n e r g i e s – R e c e n t l y r e p o r t e d 9 mo r e e v e n t s , ma k i n g t o t a l e v e n t n u mb e r 3 7 o v e r 9 8 8 d a y s

F l a v o u r @ I C F l a v o u r @ I C Muon Track Cascades Double Bang

R e c o n s t r u c t i n g e v e n t s @ I c e C u b e R e c o n s t r u c t i n g e v e n t s @ I c e C u b e Muon Tracks Cascades Charged current interaction Charged current interaction of the muon-neutrino of the electron-neutrino and tau-neutrino Clear tracks and excellent direction reconstruction Neutral current interactions of all flavours Energy reconstruction is indirect – energy loss along Excellent energy but poorer track direction reconstruction

I n c i d e n t fm u x e s f r o m s t d . t h e o r y I n c i d e n t fm u x e s f r o m s t d . t h e o r y  Di fg u s e fm u x f r o m a l l - s k y a s t r o p h y s i c a l s o u r c e s – E x p e c t e d t o f o l l o w a p o w e r - l a w s p e c t r u m ● F e r mi 1 o r d e r s h o c k s = 2 . 0 → α s t ● No r ma l i s a t i o n fj x e d b y o b s e r v a t i o n a l b e s t - fj t s – Ne u t r i n o s i n s o u r c e s p r e d o mi n a n t l y f r o m p i o n d e c a y s ● S t d . o s c i l l a t i o n i n c i d e n t fm a v o u r 1 : 1 : 1 a t e a r t h →

I n c i d e n t fm u x e s f r o m s t d . t h e o r y I n c i d e n t fm u x e s f r o m s t d . t h e o r y  Di fg u s e fm u x f r o m a l l - s k y a s t r o p h y s i c a l s o u r c e s – E x p e c t e d t o f o l l o w a p o w e r - l a w s p e c t r u m ● F e r mi 1 o r d e r s h o c k s = 2 . 0 → α s t ● No r ma l i s a t i o n fj x e d b y o b s e r v a t i o n a l b e s t - fj t s – Ne u t r i n o s i n s o u r c e s p r e d o mi n a n t l y f r o m p i o n d e c a y s ● S t d . o s c i l l a t i o n i n c i d e n t fm a v o u r 1 : 1 : 1 a t e a r t h →  C o s mo g e n i c n e u t r i n o s ( E 1 0 0 P e V ) ⩾ – C o s mi c r a y s i n t e r a c t i n g wi t h C MB R p h o t o n s

O b s e r v a t i o n s @ I C [ 6 6 2 d a y s ] O b s e r v a t i o n s @ I C [ 6 6 2 d a y s ] 2 8 t o t a l e v e n t s  T wo P e V + c a s c a d e s – Hi g h e s t e n e r g y n e u t r i n o e v e n t s e v e r o b s e r v e d  A d d i t i o n a l 1 9 l o w e r e n e r g y c a s c a d e s  7 t r a c k e v e n t s  E v e n t s f r o m 4 s k y π  No e v e n t f r o m 3 0 0 T e V – 1 P e V

O b s e r v a t i o n s @ I C [ 6 6 2 d a y s ] O b s e r v a t i o n s @ I C [ 6 6 2 d a y s ] B e s t - fj t l a r g e l y c o n s i s t e n t wi t h E p o w e r fm u x u p t o 1 . 1 P e V . . . - 2 . . . B U T ➔ Unexplained sharp drop above 1 PeV ➔ Lack of events within 300 TeV – 1 PeV ➔ Sub-100 TeV energy event numbers consistently higher σ At least 4.7 signal over atmospheric than prediction from E -2 flux neutrino background with 90% c.l. charm estimates