Atmospheric muon flux at various locations T. Sanuki University - PowerPoint PPT Presentation

Atmospheric muon flux at various locations T. Sanuki University of Tokyo

Outline 1. Data and possible source of systematic error i. Near top of the Atmosphere 5 - 30 g/cm 2 ii. Inside the Atmosphere 5 - 800 g/cm 2 iii. On the ground 800 - 1000 g/cm 2 2. Observed and calculated muon spectra

ascending/ descending floating altitude mountain ground Atm. muon & neutrino p 1. Near top of the Atmosphere 5 - 30 g/cm 2 balloon floating altitude π 2. Inside the Atmosphere γ 5 - 800 g/cm 2 ν µ balloon as(des)cending µ 3. On the ground e 800 - 1000 g/cm 2 ground/mountain ν e

On the ground 800 - 1000 g/cm 2

On the ground high statistics • infinite data taking time • infinite batteries calibrating atm. ν calculation (M.C. simulation)

On the ground • Various measurement • Two types of measurement a. Normalized b. NOT Normalized (Absolute)

Normalized Flux 1. Measure spectrum shape (not absolute intensity) 2. Calculate integrated flux above some momentum 3. Normalize the measured spectrum to a “standard” integral intensity

“Standard” Flux Range Counter • Not measure momentum p _threshold Lead 10cm p >0.44GeV/ c event by event Lead 10cm p >0.82GeV/ c • Poor momentum Iron 66cm resolution • Mult. scatt. etc. p >1.73GeV/ c Iron 66cm F p >2.68GeV/ c Iron 66cm log p p >3.64GeV/ c Barbouti and Rastine p _threshold J. Phys. G 9(1983) 1577

Normalized Flux 1. Poor statistics in higher momentum region 2. Same systematic error. Absolute Flux Measurement is important N ( p~p+ Δ p ) F ( p ) = ε ( p ) ・ S Ω ( p ) t ・Δ p

Absolute Flux P (m sr sec (GeV/ c ) ) Primary CR Spectra � � � ฀ ฀ ฀ ฀ + Hadronic Interaction ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ + Decay ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ � Production height � ฀ ฀ ฀ ฀ ฀ Altitude ฀ ฀ 2 � 10 Zenith angle � ฀ ฀ ฀ ฀ ฀ ฀ � � ฀ ฀ ฀ ฀ ฀ ฀ ฀ � � � ฀ ฀ ฀ ฀ ฀ ฀ ฀ � + � Flux � ฀ ฀ ฀ site altitude R c ฀ ฀ ฀ MASS-89 Prince Albert 600m 0.7GV ฀ ฀ ฀ CAPRICE-97 Ft. Sumner 1270m 4.3GV ฀ ฀ ฀ CAPRICE-94 Lynn Lake 360m 0.4GV ฀ ฀ ฀ ฀ BESS-02 Tsukuba 30m 11.4GV � BESS-97/98/99Lynn Lake 360m 0.4GV ฀ ฀ 10 ฀ BESS-99 Mt. Norikura 2770m 11.2GV ฀ ฀ ฀ L3+C Geneva 450m 4.42GV � CosmoALEPH Geneva 450m 4.42GV Different 2 3 1 10 10 10 experimental condition Momentum P (GeV/ c )

Different Condition • Altitude • Atmospheric Structure; ρ ( h ) • Zenith Angle • Geomagnetic Cutoff Rigidity • (Solar Modulation)

BESS Data summary site cutoff Rigidity atm. pressure date Dec. 95 Tsukuba May. 97 1030 g/cm 2 11.4 GV Nov. 97 Japan Oct. 02 740 g/cm 2 Mt. Norikura 11.2 GV Sep. 99 890 g/cm 2 Sep. 01 Ft. Sumner 800 to 5 g/cm 2 4.3 GV NM, USA Sep. 01 5 to 30 g/cm 2 Jul. 97 Jul. 98 1000 g/cm 2 Lynn Lake Jul. 99 0.4 GV MB, Canada Jul. 00 Aug. 99 800 to 5 g/cm 2 Aug. 00

10% effect Rc<1GV @1GeV/c Rc=11GV Geomagnetic Field 40 µ +µ Flux (m sr sec (GeV/c) ) + � � 2 � 1 � 1 � 1 30 20 10 9 8 7 6 site altitude R c 5 MASS-89 Prince Albert 600m 0.7GV CAPRICE-94 Lynn Lake 360m 0.4GV BESS-97/98/99Lynn Lake 360m 0.4GV 4 BESS-95/02 Tsukuba 30m 11.4GV 3 1 5 Momentum P (GeV/ c ) Altitude correction is important, but...

@1GeV/c ex) BESS; Almost same condition except for altitude 30~40% effect Altitude Flux (m sr sec (GeV/ c ) ) � + � - -2 -1 -1 -1 2770m a.s.l. 10 30m a.s.l. 1 Tsukuba, Japan Tsukuba, Japan -1 Mt. Norikura, Japan Mt. Norikura, Japan 10 1 10 1 10 Momentum P (GeV/ c ) Momentum P (GeV/ c ) Huge effect on flux in low momentum region

surface December May (winter) (spring) High <-- density --> Low Seasonal variation in muon 25 Altitude (km) x 10 -2 Density � ( h ) (g/cm ) 0.12 3 20 0.1 15 0.08 0.06 10 0.04 5 0.02 0 0 0 10 20 30 40 1995 Dec. 1997 May. Altitude h (km)

ex) BESS; Same condition except for zenith angle Vertical BESS@Tsukuba,Japan “Vertical”/“Near vertical” Zenith Angle 1.2 >0.90) 8 9 cosθ=0.90 . 0 = θ � s 1.1 o >0.98) / F(cos c 1.0 � 0.9 F(cos 0.8 2 3 1 10 10 10 Momentum (GeV/ c ) Experimental/Analysis condition should be considered

Inside the Atmosphere 5 - 800 g/cm 2

Balloon ascending period Flux vs Residual Atmospheric depth growth curve ~5 - 800 g/cm 2 p + A π + π + · · · → µ + ν µ π → µ e + ν e + ν µ → Indirect measurement of atm. ν production

ex) BESS Y. Yamamoto Growth curve 10 2 Flux (m sr sec (GeV/ c ) ) -2 -1 -1 -1 µ + µ � 1.12 GeV/ c 1.12 GeV/ c 10 2.04 GeV/ c 1 2.04 GeV/ c 1999 Lynn Lake 5.79 GeV/ c 2000 Lynn Lake 2001 Ft. Sumner -1 10 10 2 10 3 1 10 2 10 3 1 10 10 2 2 Atm. depth (g/cm ) Atm. depth (g/cm ) Poor statistics

Near Top of the Atmosphere 5 - 30 g/cm 2

Balloon altitude Thin target ~5 - 30 g/cm 2 < 100g/cm 2 p + A π + π + · · · → µ + ν µ π → µ e + ν e + ν µ → sensitive to hadronic interaction model

Good statistics during slow descending. BESS-01 ex) BESS; Unique balloon flight at Ft. Sumner, NM, US. 5 to 30 g/cm 2 Decent data � Balloon altitude 3 P 2 (m -2 sr -1 sec -1 (GeV/ c )/(g/cm 2 )) � - + 2 1 0.9 0.8 0.7 0.6 DPMJET-III 0.5 Fritiof1.6 Flux/Depth � FLUKA97 0.4 Fritiof7.02 0.3 1 10 1 10 Momentum P (GeV/ c ) Momentum P (GeV/ c ) Honda-san’s talk...

Perfect MC ?

M. Honda http://nssdc.gsfc.nasa.gov/space/model/atmos/nrlmsise00.html MC simulation 1. input spectrum - BESS data + power-law extrapolation 2. hadronic interaction - DPMJET-III - based 3. same condition as BESS observation - latitude and longitude (geomagnetic R c ) - altitude - date • observed ρ ( h ) data + NRLMSISE-00 Model • solar modulation - zenith angle

MC < DATA Not perfect ... P (m sr sec (GeV/ c ) ) Flux (m sr sec (GeV/ c ) ) � � + � - � -2 -1 -1 -1 2770m a.s.l. � ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ ฀ 10 ฀ � � ฀ ฀ ฀ ฀ 30m a.s.l. ฀ ฀ ฀ 2 � 10 � ฀ ฀ ฀ ฀ ฀ ฀ � � ฀ ฀ ฀ ฀ ฀ ฀ 1 ฀ � � � DPMJET-III DPMJET-III ฀ ฀ ฀ ฀ ฀ ฀ ฀ � + � Flux � ฀ ฀ ฀ ฀ ฀ ฀ DPMJET-III ฀ ฀ ฀ ฀ ฀ ฀ Tsukuba, Japan Tsukuba, Japan BESS-02 Tsukuba ฀ ฀ ฀ ฀ -1 � Mt. Norikura, Japan Mt. Norikura, Japan ฀ ฀ 10 ฀ 10 ฀ ฀ ฀ � 2 3 1 10 10 10 1 10 1 10 Momentum P (GeV/ c ) Momentum P (GeV/ c ) Momentum P (GeV/ c ) Honda-san’s talk...

Summary Many experiments at various locations • Site (Cutoff Rigidity, Altitude) • Date (Solar modulation, atm. structure) • Zenith angle Huge effect on flux in low momentum region • Calculation under the same condition as experiment For controlling systematic error in neutrino calculation.