Jpp PDF time arrival dependence on direction Jordan Seneca August - - PowerPoint PPT Presentation

▶

Aug 14, 2022 244 likes •356 views

Jpp PDF time arrival dependence on direction Jordan Seneca August 20 th 2020, update Jordan Seneca 1 cd = 0.74 A few months back, I showed this cd = -0.5 WRONG Plot information Cherenkov RIGHT angle has the least early light Jordan

SLIDE 1

Jordan Seneca 1

Jpp PDF time arrival dependence

n direction

Jordan Seneca August 20th 2020, update

SLIDE 2

Jordan Seneca 2

A few months back, I showed this Plot information cd = -0.5 cd = 0.74

WRONG

RIGHT

Cherenkov angle has the least early light

SLIDE 3

Jordan Seneca 3

SLIDE 4

Jordan Seneca 4

Cos(angle) dependence on the elongated time residual pdf Plot information Forward: a narrow distribution centered at dt ~ 1 ns and some late contribution Backward: a wide distribution centered at dt ~ 7 ns with early ( up to -25 ns! ) and late contributions cd = 0.74 cd = -0.99

SLIDE 5

Jordan Seneca 5

Cos(angle) dependence on the elongated time residual pdf Plot information Plot information cd = 1.0 cd = 0.74 cd = 0.0 cd = -0.5

Note! earlier light here than at cherenkov angle!

SLIDE 6

Jordan Seneca 6

Cos(angle) dependence on the raw time residual pdf Plot information With point-like showers, there is no difference in early light, but more late (scattered) light in the backward direction. → Shower elongation helps with direction estimation! cd = 0.74 cd = -0.5

SLIDE 7

Jordan Seneca 7

How does this work?

→ Heuristic explanation

SLIDE 8

Jordan Seneca 8

Point-like shower case

cos(a) = 0.74 (cherenkov) cos(a) = -0.5 cos(a)

All early light comes from the same point, but some late light is reflected backward from the bright cherenkov cone region

shower plotted angle late light

SLIDE 9

Jordan Seneca 9

Elongated shower case, with shower max as origin

cos(a) = 0.74 (cherenkov) cos(a) = -0.5 cos(a)

(from shower max)

In the backward and forward region, light emitted from the start and end of the shower respectively arrives early

cos(a) = 1.0

By definiton, light from the entire shower arrives to the cherenkov angle point at the same time → no early light

shower plotted angle early light late light

SLIDE 10

Jordan Seneca 10 Conclusion:

The light arrival time distribution is sensitive to the neutrino direction! The elongated shower’s sequential light emittance informs its direction. cd = -0.99 cd = 0.74

SLIDE 11

Jordan Seneca 11

Sidenote, elongated pdfs cd = -0.5 cd = -0.99 High dt bump for extremely backward directions. Maybe due to interpolation issues in the PDFs?