Event classification by visual inspection

 

Table 13: Classification of the experimental events that are nearly up-going ( $-1 < \cos \theta(2) < -0.92$). The first two columns labeled $\nu$ Cand. are candidate up-going neutrino-induced muons. The first column contains events that are common to both UCI and Zeuthen atmospheric neutrino Analysis. The second lists neutrino candidate found in this work. The column listing cascade-like events have more of a spherical hit topology expected from a cascade event. Down-going muon events are more consistent with a down-going muon. Noise/? events have no correlation with a cascade or muon event topologies. Each number given is the ievent number of the event and the GPS day and GMT second of the event (ievent, gpsday:gmtsec).

$\nu$ Cand.(Zeuthen)	$\nu$ Cand.(UCI)	Cascade like		Down-going muon	Noise/?
1528728, 100:30458	10428633, 168:81141	10681080, 135:5709	218998, 207:85835	6314559, 133:2090	5031872, 126:23810
49481, 116:15134	587900, 231:84460	2217936, 137:81238	2844964, 243:9736		6009947, 126:36861
3911386, 155:65086	5873229, 251:16110	2951686, 138:75806	3030310, 245:59324		6951259, 147:38143
486617, 169:46474	81294, 261:20006	4266659, 145:43851	528695, 247:69091		4017238, 154:50314
2976350, 176:59351	1892418, 279:25547	678009, 144:83416	697555, 255:63266		4531603, 168:6042
2757832, 197:63962	1258066, 315:617	5266659, 147:17034	390452, 273:77736		6281, 189:46503
2627233, 200:73755		613171, 149:63210	743551, 279:68290		891836, 245:77227
4366149, 228:41888		2902600, 155:51984	3223491, 281:57420
1936710, 241:79745		1112845, 155:28472	240629, 285:5920
177052, 279:60890		3630785, 171:57360	327939, 289:7800
1197960, 285:18132		116256, 175:31885	4693247, 291:31249
8301190, 303:35604		2598822, 178:10496	2586747, 292:45723
		1470922, 186:46886	1700469, 294:11408
		3713154, 193:79511	1451062, 295:43335
		539455, 197:35297	1048078, 299:27424
		1674321, 197:49901	2987199, 305:26981
		615637, 203:28461	6932374, 309:83521
		1009328, 203:77061

Table 13 for five classes of topologies. Events are nearly up going (ie. $-1 < \cos \theta(2) < -0.92$). The conclusion from this table is most of the events that pass our selection criteria are Cascade-like events (57.3%). There are only 18 neutrino candidates, which is $\sim 2/5$ less than what Monte Carlo predicts ($\sim 50$ events, figure 34). Another approach to investigate the number of atmospheric neutrinos in our data set is to find how many neutrino candidates found in the analysis done at Zeuthen pass our selection criteria.

Table 14 shows the neutrino candidates found from the analysis done at Zeuthen [6] that pass the UCI filter (total of 93 events). There are 32 events that pass our set of cuts. The table includes the values for each event of the variables in our analysis. There are only 36 of the 93 events that pass the jkrchi(3) cut of 4.1, while all the cuts on the other variables (table 2) pass the events with an efficiency greater than 90%. This may be related to the energy dependence in this variable (figure 1), in which the low energy atmospheric neutrinos are more efficiently removed by this cut.

 

Table 14: The x in the first column denote the events that pass the optimized cuts. Brief definition of each of the variables: ievent - event ID number, gpsday - day of event, gmtsec - second of the event - zenith - zenith angle of the full reconstructed event in degrees, azimuth - azimuth angle of the full reconstructed event in degrees, ndirc - number of direct hits in -15:25ns time window, ndirc - number of direct hits in -15:75ns time window, ldirb - projected length of hits in -15:25ns time window (units in meters), ldirc - projected length of hits in -15:75ns time window (units in meters), jkrchi(full) - likelihood parameter of the full reconstructed fit, jkrchi(EF) - likelihood parameter of the energy reconstruction, zen. diff - zenith angle difference between the ful reconstruction fit and the line fit (units in degrees).

pass	ievent	gpsday	gmtsec	zenith	azimuth	ndirb	ndirc	ldirb	ldirc	jkrchi(full)	jkrchi(EF)	zen. diff
x	1984898	96	59847	126.85	286.945	8	13	148.316	150.253	6.96187	3.98224	-13.9529
x	1528728	100	30458	156.621	354.935	16	21	314.454	314.454	6.96314	3.61975	-8.80566
	2570660	112	4687	165.932	211.067	12	22	255.321	331.967	7.0104	4.6682	-8.55023
	1515357	112	78585	129.998	257.216	5	12	145.496	151.464	7.67552	5.6539	-12.4999
x	11671	114	42142	111.675	257.172	9	13	98.9004	123.991	7.52968	3.67823	-11.2584
	105696	115	1189	139.718	107.19	4	7	151.969	151.969	7.37951	4.32867	4.56215
	168651	117	32466	140.512	238.759	9	12	107.095	107.095	7.15532	4.35731	3.664
x	49481	116	15134	165.33	244.735	16	30	284.441	380.128	6.41002	3.43425	-0.903641
	1332456	122	76340	168.472	25.5381	10	13	197.681	216.426	6.90485	4.99986	8.68207
	1422957	122	77541	149.534	292.938	5	9	42.6502	68.0416	7.72486	5.13985	45.4978
	333605	125	36977	115.292	130.465	5	5	95.5171	95.5171	7.39092	2.78665	0.184029
	397392	130	20631	131.014	246.762	11	16	147.922	160.91	7.1113	4.11824	-16.7819
	1836608	130	40222	128.517	188.116	10	13	151.595	151.595	7.41447	4.56912	23.3848
x	10604848	131	73508	147.505	243.928	18	21	279.506	279.506	6.79153	3.92041	-2.93063
	910225	133	52246	169.64	25.5821	13	17	325.108	325.108	7.0514	4.56865	-0.307617
	104596	138	37977	132.555	236.38	12	16	175.118	175.118	6.96218	3.21426	32.5612
x	2312069	138	67355	143.81	15.5514	12	16	204.358	220.182	6.82109	3.7209	-3.14488
	5362470	139	21345	148.524	305.919	6	15	104.149	354.67	7.03081	4.84445	-7.88005
x	3391162	142	73198	111.153	1.63149	10	13	117.082	122.881	7.23129	3.33781	-8.42939
	3694138	142	76962	148.408	245.554	12	24	179.154	220.813	6.56172	4.18971	-0.585037
	4248207	144	3234	160.452	292.982	6	12	321.062	321.062	7.26843	5.60379	12.6509
	5570896	144	20249	153.855	331.155	10	27	274.345	296.607	6.67598	4.1721	1.73862
	99192	148	13565	135.203	255.859	9	13	180.976	180.976	7.65315	5.13607	2.24399
x	3911386	155	65086	170.302	9.41543	17	20	254.551	254.551	6.58848	3.97653	-4.4413
	3060723	156	81150	171.546	200.114	9	13	126.697	196.678	7.30486	4.14519	-2.44998
	6942749	160	30877	149.968	8.84413	9	14	240.661	267.375	7.5334	4.81897	-6.65233
	625030	162	17469	169.005	321.805	22	30	483.234	512.082	6.32978	4.25347	-8.82765
x	3568652	163	71	131.668	60.3543	11	13	168.003	168.003	7.1954	3.90154	7.0808
	2075061	166	74684	159.873	65.9409	14	20	326.828	326.828	6.64858	4.47728	-6.33646
	2939981	169	78421	121.225	288.577	8	12	131.692	147.044	8.03052	4.63047	2.26871
x	486617	169	46474	165.152	352.947	10	18	154.093	223.297	6.90969	3.51936	-5.03456
	5178189	170	21153	160.101	245.51	12	20	355.949	355.949	6.68177	4.42964	-3.83704
x	2636618	176	55019	112.348	30.0865	8	14	125.46	132.99	7.20177	3.16969	-4.43031
x	2976350	176	59351	172.087	126.669	19	22	323.318	323.318	6.29921	3.46701	-3.20805
	7599807	177	31966	143.184	95.5166	8	14	199.034	254.159	7.24281	4.34066	-0.51088
	1222689	177	79448	145.423	255.958	12	14	229.593	229.593	6.9795	4.31259	-4.3589
	8859374	179	5118	112.323	79.3005	6	14	126.923	141.844	7.35381	4.24063	-8.29205
	4760153	192	1280	162.74	21.572	8	17	366.673	375.542	6.98321	5.5563	1.02449
	1443101	194	35109	173.537	241.555	4	12	58.5495	389.495	7.05661	4.69381	-0.0439453
x	2757832	197	63962	176.49	145.302	15	20	153.765	153.765	6.69522	3.09298	-2.41154
	1720882	198	27065	144.714	333.924	5	11	186.527	267.673	7.35216	5.39695	0.0137329
x	1825306	200	26094	133.846	119.561	7	14	152.952	166.605	7.10272	3.51997	0.535599
x	2627233	200	73755	157.055	294.954	11	16	246.632	246.632	6.90973	3.66492	0.332336
	2995880	202	5311	131.577	331.188	7	13	143.095	143.095	7.52729	4.70222	-17.6196
	7085339	202	58586	151.229	222.488	9	11	224.785	224.785	7.50114	4.84928	-7.27856
x	3309224	209	85244	143.764	121.989	10	16	226.355	226.355	6.99812	4.0434	-3.30418
x	4176635	210	9887	150.04	334.281	13	17	148.821	198.994	6.71424	3.76838	11.6512
	158287	211	40869	145.269	94.3795	7	9	187.545	204.126	7.23143	3.62721	-15.4113
	1960937	211	64009	138.883	217.917	3	4	86.0546	161.452	7.25765	4.53877	-13.0712
	466656	218	13477	149.306	16.9796	7	12	81.8873	110.552	7.25948	5.88244	9.13527
	3807358	223	32245	149.633	10.1021	6	9	250.306	250.306	7.04315	4.77765	-8.11353
	3562282	224	18795	131.368	253.189	9	14	166.362	166.362	7.41007	4.59863	-20.2262
	2216336	227	55886	175.767	281.699	12	15	259.287	259.287	6.29703	4.45533	5.41635
	1848998	227	51004	141.448	3.60357	4	8	189.974	212.951	6.88192	3.93151	-2.85374
x	4366149	228	41888	166.297	161.469	17	21	342.038	351.337	6.2835	3.70851	-1.68094
	217835	230	4125	139.649	262.215	9	14	188.851	188.851	7.3969	4.66979	-6.47653
	10705083	231	50261	143.346	336.868	2	3	177.038	200.718	7.54756	4.94959	18.8034

pass	ievent	gpsday	gmtsec	zenith	azimuth	ndirb	ndirc	ldirb	ldirc	jkrchi(full)	jkrchi(EF)	zen. diff
x	1208852	233	59393	154.206	285.742	9	15	149.457	164.436	6.83403	3.80302	-10.5388
	1187361	234	44450	146.464	294.938	6	12	226.308	226.308	7.01904	4.68886	-1.24698
	756991	238	33968	133.343	168.011	6	12	142.211	163.649	7.80322	4.20249	-4.58687
x	1936710	241	79745	178.459	117.187	33	39	343.779	343.779	5.4269	2.03007	0.324097
x	3570940	240	3760	130.833	299.459	7	13	140.631	191.989	7.23481	3.44266	-1.11513
	1389265	244	51953	160.452	233.534	12	15	321.095	321.095	7.11017	5.17065	-5.27902
	2422641	246	25298	152.295	69.9345	10	13	217.151	250.813	7.06628	4.51367	3.65575
	2172961	246	62099	158.697	5.59762	6	14	93.2911	294.574	7.24371	5.0212	3.18333
	4305038	250	19398	146.359	272.553	10	14	227.267	235.246	7.14221	4.54502	-10.4125
x	14222751	252	21966	120.343	196.301	9	20	139.204	153.882	6.79798	3.18513	-9.962
	18088672	252	61336	170.832	181.151	10	12	220.561	249.106	7.44405	5.3292	0.771805
	2340945	256	67267	146.64	354.726	9	15	221.631	280.017	7.16039	5.11036	-23.1623
	9765274	258	4217	158.423	327.854	10	19	333.612	333.612	6.99139	4.83296	0.889893
	5530269	260	81813	145.799	208.573	8	13	195.13	195.13	7.18716	4.39456	-7.67955
x	1021539	261	33065	112.386	238.687	10	17	119.897	127.443	7.14277	3.43784	-0.0302124
	569921	275	1037	122.033	79.5312	9	13	156.395	156.395	7.3819	4.50906	-15.013
x	112258	279	60044	144.08	160.106	6	14	128.587	152.454	7.25158	3.21853	-7.36369
x	177052	279	60890	163.114	110.782	13	20	158.425	318.379	6.49304	3.49383	-9.86313
	2969650	280	71918	156.239	113.979	5	11	29.5233	109.056	7.74835	5.21234	16.7352
x	1001647	280	46749	146.464	141.545	11	15	227.912	229.06	7.17503	3.9051	-4.38911
	3023227	284	65079	114.246	23.2639	9	16	116.391	136.749	7.23748	4.62259	-28.8258
x	1197960	285	18132	157.038	261.457	17	27	336.822	336.822	6.29184	3.22662	-0.123596
	454402	287	85276	171.579	23.9835	8	14	238.838	238.838	7.20871	5.02212	9.62143
	6089102	290	26256	143.442	194.368	8	12	171.906	204.601	7.17161	4.40002	4.16113
	1229085	292	28720	144.06	338.027	10	19	193.221	218.257	7.02445	4.54938	-10.7723
	296959	293	5163	150.301	106.382	7	14	214.657	234.568	7.19836	5.02586	-3.86176
	2859301	294	25839	135.326	16.9467	10	15	147.936	195.639	6.93167	4.20806	-12.8377
	1552180	295	44611	143.33	257.09	8	15	197.494	308.413	7.46403	4.63539	-10.5251
	505876	302	23110	109.934	111.595	6	13	112.4	119.047	7.29804	4.88106	19.339
x	8301190	303	35604	164.523	32.7178	14	18	219.393	276.673	6.72592	3.63479	-6.83633
x	1309726	303	69333	118.047	227.42	7	13	125.133	125.133	7.38282	4.06818	-21.182
	4894124	304	27502	169.412	146.214	8	16	185.435	232.711	7.30313	5.39412	2.68893
x	8452210	304	71447	118.11	54.1415	7	11	126.212	126.212	7.28874	3.92807	-17.2213
x	8248715	307	82811	156.324	165.451	15	19	207.81	234.76	6.64077	3.89146	-2.20006
	535305	308	40316	156.431	50.8345	9	18	255.371	264.362	6.88412	4.24896	-5.34494
x	1695439	311	85155	125.941	70.2367	10	18	140.907	158.19	6.8429	3.44838	-19.751