Welcome to Sherpa, Daniel Reichelt on ip3-cpu4.phyip3.dur.ac.uk. Initialization of framework underway ... Local time: Thu Apr 24 15:05:57 2025 Seed mode: '*' Memory limit: 502.838 GB Seed: 1037 ┌──────────────────────────────────────────────────────────────────────────────┐ │  ._ │ │  .-#. │ │  .--+@. . │ │  .----@@. +#- │ │  .-----+@@. +**@- SHERPA v3.1.x (Erebus) │ │  :- .-------@@@+***#@- │ │  :=#* .--------+@+*****@@- Monte Carlo event generator │ │  :===@* .----------+******#@@- │ │  :====#@*----------+********@@@- https://sherpa-team.gitlab.io │ │  :======@@*--------+*********#@@@- │ │ │ │ Authors: Enrico Bothmann, Lois Flower, Christian Gutschow, │ │ Stefan Hoeche, Mareen Hoppe, Joshua Isaacson, │ │ Max Knobbe, Frank Krauss, Peter Meinzinger, │ │ Davide Napoletano, Alan Price, Daniel Reichelt, │ │ Marek Schoenherr, Steffen Schumann, Frank Siegert │ │ Former Authors: Gurpreet Singh Chahal, Timo Fischer, Tanju Gleisberg, │ │ Hendrik Hoeth, Johannes Krause, Silvan Kuttimalai, │ │ Ralf Kuhn, Thomas Laubrich, Sebastian Liebschner, │ │ Andreas Schaelicke, Holger Schulz, Jan Winter │ │ │ │ Users are kindly asked to cite JHEP 12 (2024) 156. │ │ │ │ This program uses a lot of genuine and original research work by others. │ │ Users are encouraged to also cite the various original publications. │ │ │ └──────────────────────────────────────────────────────────────────────────────┘ WARNING: You are using an unsupported development branch. Git branch: fix-loop-mur-dependence Revision: 90f4b940a9567813fb3c9cea3c411e2907920ee4. Initializing hadron particle information ... Initializing beam spectra ... Type: Collider Setup Beam 1: P+ (enabled = 0, momentum = (6800,0,0,6800)) Beam 2: P+ (enabled = 0, momentum = (6800,0,0,-6800)) Initializing PDFs ... Hard scattering: PDF4LHC21_40_pdfas + PDF4LHC21_40_pdfas MPI: PDF4LHC21_40_pdfas + PDF4LHC21_40_pdfas Fixed electroweak parameters Input scheme: Gmu scheme, input: GF, m_W, m_Z, m_h, widths Ren. scheme: Gmu Parameters: sin^2(\theta_W) = 0.223043 - 0.00110541 i vev = 246.22 Set \alpha according to EW scheme 1/\alpha(0) = 137.036 1/\alpha(def) = 132.12 Particle data: ┌─────────────────────────────────────────────────────────────────────────────────────────┐ │ Name Kf-code Mass Width Stable Massive Active Yukawa │ ├─────────────────────────────────────────────────────────────────────────────────────────┤ │ d 1 0.01 0 1 0 1 0 │ │ u 2 0.005 0 1 0 1 0 │ │ s 3 0.2 0 1 0 1 0 │ │ c 4 1.42 0 1 0 1 0 │ │ b 5 4.92 0 1 0 1 0 │ │ t 6 172.5 1.32 0 1 1 172.5 │ │ e- 11 0.000511 0 1 0 1 0 │ │ ve 12 0 0 1 0 1 0 │ │ mu- 13 0.105 0 1 0 1 0 │ │ vmu 14 0 0 1 0 1 0 │ │ tau- 15 1.777 2.26735e-12 0 0 1 0 │ │ vtau 16 0 0 1 0 1 0 │ │ G 21 0 0 1 0 1 0 │ │ P 22 0 0 1 0 1 0 │ │ Z 23 91.1876 2.4952 0 1 1 91.1876 │ │ W+ 24 80.379 2.085 0 1 1 80.379 │ │ h0 25 125 0 0 1 1 125 │ │ Instanton 999 0 0 0 0 1 0 │ └─────────────────────────────────────────────────────────────────────────────────────────┘ Particle containers: ┌─────────────────────────────────────────────────────────────────────────────────────────┐ │ Name Kf-code Constituents │ ├─────────────────────────────────────────────────────────────────────────────────────────┤ │ l 90 e-, e+, mu-, mu+, tau-, tau+ │ │ v 91 ve, veb, vmu, vmub, vtau, vtaub │ │ f 92 d, db, u, ub, s, sb, c, cb, b, bb, e-, e+, mu-, mu+, │ │ tau-, tau+, ve, veb, vmu, vmub, vtau, vtaub │ │ j 93 d, db, u, ub, s, sb, c, cb, b, bb, G │ │ Q 94 d, db, u, ub, s, sb, c, cb, b, bb │ │ ewj 98 d, db, u, ub, s, sb, c, cb, b, bb, G, P │ └─────────────────────────────────────────────────────────────────────────────────────────┘ Reading in parameters for P+ yields: Primordial k_T Form = None Primordial k_T Recoil = Beam_vs_Shower Matter Form = Single_Gaussian BEAM_SPECTATOR_KTEXPO = 5 BEAM_SPECTATOR_KTMAX = 1 BEAM_SPECTATOR_MEAN = 0 BEAM_SPECTATOR_Q2 = 0.77 BEAM_SPECTATOR_SIGMA = 0.25 ENERGY_SCALING_EXPO = 0.08 MATTER_FRACTION_1 = 1 MATTER_RADIUS_1 = 0.86 MATTER_RADIUS_2 = 0 REFERENCE_ENERGY = 7000 SHOWER_INITIATOR_KTEXPO = 5.12 SHOWER_INITIATOR_KTMAX = 2.7 SHOWER_INITIATOR_MEAN = 1 SHOWER_INITIATOR_Q2 = 0.77 SHOWER_INITIATOR_SIGMA = 1.1 Initializing primordial transverse momentum ... Initializing remnants ... Hard process: P+ (Hadron) + P+ (Hadron) Initializing showers ... Initializing matrix elements for the hard processes ... Initializing Comix ... Massive PS flavours for Comix: (c,cb,b,bb,e-,e+,mu-,mu+,tau-,tau+) Massive PS flavours for Amegic: (c,cb,b,bb,e-,e+,mu-,mu+,tau-,tau+) Massive PS flavours for Internal: (c,cb,b,bb,e-,e+,mu-,mu+,tau-,tau+) Building processes (3 ME generators, 1 process blocks) ... Setting up processes ME_Generators::LoadGenerator(): Try loading 'OpenLoops' from 'libSherpaOpenLoops'. Initialising OpenLoops generator from /mt/home/dreichelt/hepsoftware/src/OpenLoops/. #################################################################### # ___ ___ ____ _ _ __ __ ___ __ ___ # # / \ |__| |__ |\ | | / \ / \ |__| /__ __/ # # \___/ | |___ | \| |__ \__/ \__/ | __/ /__ # # You are using OpenLoops 2 to evaluate loop amplitudes # # F. Buccioni, J.-N. Lang, J. Lindert, P. Maierhoefer, # # S. Pozzorini, M. Zoller, H. Zhang # # Eur.Phys.J. C79 (2019) no.10, 866 # # arXiv:1907.13071 # #################################################################### ......................................................................................................................................................................................................................................................................................................................................................... done (262 MB, 11s/10s) Performing tests . Amplitude::GaugeTest(): Large deviation { 5.93399354094e-23 vs 5.93399354092e-23 => 3.98436839077e-12 } ........ Amplitude::GaugeTest(): Large deviation { 4.03627645703e-23 vs 4.03627645702e-23 => 3.37996297617e-12 } . Amplitude::GaugeTest(): Large deviation { 1.50165940863e-24 vs 1.50165940865e-24 => -1.23335786029e-11 } ... Amplitude::GaugeTest(): Large deviation { 2.51117513309e-20 vs 2.5111751331e-20 => -2.19724238804e-12 } .. Amplitude::GaugeTest(): Large deviation { 6.48399026498e-21 vs 6.48399026501e-21 => -5.07560660168e-12 } ..... Amplitude::GaugeTest(): Large deviation { 2.21739412352e-23 vs 2.2173941235e-23 => 1.24016352743e-11 } .WARNING: last allowed error message from 'GaugeTest'  Amplitude::GaugeTest(): Large deviation { 1.78736939518e-21 vs 1.78736939518e-21 => -2.59126053948e-12 } ................................................................................................................... done (262 MB, 0s/0s) Initializing scales........................................................................ done (264 MB, 0s/0s) Initializing the beam remnants ... Multiple interactions initialized id = 2, name = None, type = 0 Underlying event/multiple interactions initialized MI[2]: on = 0 (type = 0, None) Initialized fragmentation Initialized soft photons Initialized on-the-fly reweighting Read in channels from directory: Results/Amegic/MC_2_3__j__j__h0__j__j__QCD(BVI) Calculating xs for '2_3__j__j__h0__j__j__QCD(BVI)' (Amegic+OpenLoops) ... 2_3__j__j__h0__j__j__QCD(BVI) : 5.96100664476 pb +- ( 0.0634172095454 pb = 1.06386745268 % )  exp. eff: 0.104225558705 % Read in channels from directory: Results/Comix/MC_2_4__j__j__h0__j__j__j__QCD(RS) Calculating xs for '2_4__j__j__h0__j__j__j__QCD(RS)' (Comix) ... 2_4__j__j__h0__j__j__j__QCD(RS) : 0.156547087194 pb +- ( 0.0550446800857 pb = 35.1617401973 % )  exp. eff: 0.000272710578471 % reduce max for 2_3__j__j__h0__j__j__QCD(BVI) to 0.39657075534 ( eps = 0.001 -> exp. eff 0.00262817056735 ) reduce max for 2_4__j__j__h0__j__j__j__QCD(RS) to 0.456062791903 ( eps = 0.001 -> exp. eff 5.97967173191e-06 ) ┌──────────────────────────────────────────────────────────────────────────────┐ │ SHERPA generates events with the following structure: │ │ Event generation Weighted │ │ Perturbative Signal_Processes │ │ Perturbative Minimum_Bias: None │ │ Perturbative Hard_Decays │ │ Perturbative Jet_Evolution:CSS │ │ Perturbative Lepton_FS_QED_Corrections:Photons │ │ Perturbative Multiple_Interactions: None │ │ Hadronization Beam_Remnants:Parametrised │ │ Hadronization Hadronization: None │ │ Hadronization Hadron_Decays │ │ Userhook None │ │ Analysis Rivet │ │ Reweighting 6 variations │ └──────────────────────────────────────────────────────────────────────────────┘ Event 1 ( 1s elapsed / 19d 13h 26m 38s left ) -> ETA: Wed May 14 04:32 XS = 7.7833550153e-12 pb +- ( 7.7833550153e-12 pb = 100 % ) Event 2 ( 1s elapsed / 9d 20h 6m 38s left ) -> ETA: Sun May 04 11:12 XS = 0.0881981904112 pb +- ( 0.0881981904034 pb = 99 % ) Event 3 ( 1s elapsed / 6d 13h 24m 24s left ) -> ETA: Thu May 01 04:30 XS = 0.0661578267551 pb +- ( 0.0661455820544 pb = 99 % ) Event 4 ( 1s elapsed / 4d 22h 44m 58s left ) -> ETA: Tue Apr 29 13:51 XS = 11.6136946056 pb +- ( 11.5476504451 pb = 99 % ) Event 5 ( 1s elapsed / 3d 23h 33m 18s left ) -> ETA: Mon Apr 28 14:39 XS = 9.67807883799 pb +- ( 9.62524955177 pb = 99 % ) Event 6 ( 1s elapsed / 3d 7h 37m 44s left ) -> ETA: Sun Apr 27 22:43 XS = 8.30095549615 pb +- ( 8.25056210691 pb = 99 % ) Event 7 ( 1s elapsed / 2d 20h 15m 12s left ) -> ETA: Sun Apr 27 11:21 XS = 14.7790132108 pb +- ( 9.64463908419 pb = 65 % ) Event 8 ( 1s elapsed / 2d 12h 4m 8s left ) -> ETA: Sun Apr 27 03:10 XS = 13.1369006318 pb +- ( 8.66283405608 pb = 65 % ) Event 9 ( 1s elapsed / 2d 5h 23m 40s left ) -> ETA: Sat Apr 26 20:29 XS = 11.8232105687 pb +- ( 7.85885085038 pb = 66 % ) Event 10 ( 1s elapsed / 2d 19m 58s left ) -> ETA: Sat Apr 26 15:26 XS = 10.7483732442 pb +- ( 7.1893978646 pb = 66 % ) Event 20 ( 1s elapsed / 1d 43m 18s left ) -> ETA: Fri Apr 25 15:49 XS = 5.06181334584 pb +- ( 3.39196988981 pb = 67 % ) Event 30 ( 1s elapsed / 16h 56m 38s left ) -> ETA: Fri Apr 25 08:02 XS = 9.26107587304 pb +- ( 5.37289322842 pb = 58 % ) Event 40 ( 1s elapsed / 12h 59m 8s left ) -> ETA: Fri Apr 25 04:05 XS = 7.06431313339 pb +- ( 4.11544691749 pb = 58 % ) Event 50 ( 1s elapsed / 10h 36m 38s left ) -> ETA: Fri Apr 25 01:42 XS = 5.67887490761 pb +- ( 3.40083637144 pb = 59 % ) Event 60 ( 1s elapsed / 9h 1m 38s left ) -> ETA: Fri Apr 25 00:07 XS = 7.34732233696 pb +- ( 3.82632551226 pb = 52 % ) Event 70 ( 1s elapsed / 7h 51m 23s left ) -> ETA: Thu Apr 24 22:57 XS = 6.40199469458 pb +- ( 3.34440435072 pb = 52 % ) Event 80 ( 2s elapsed / 7h 2m 52s left ) -> ETA: Thu Apr 24 22:09 XS = 5.66966657516 pb +- ( 2.93630750761 pb = 51 % ) Event 90 ( 2s elapsed / 6h 23m 17s left ) -> ETA: Thu Apr 24 21:29 XS = 5.12463926404 pb +- ( 2.64342051206 pb = 51 % ) Event 100 ( 2s elapsed / 5h 49m 57s left ) -> ETA: Thu Apr 24 20:56 XS = 4.76872439721 pb +- ( 2.38289563781 pb = 49 % ) Event 200 ( 2s elapsed / 3h 26m 37s left ) -> ETA: Thu Apr 24 18:32 XS = 4.8010727639 pb +- ( 2.08068293087 pb = 43 % ) Event 300 ( 2s elapsed / 2h 37m 43s left ) -> ETA: Thu Apr 24 17:43 XS = 4.42176360747 pb +- ( 1.52166721486 pb = 34 % ) Event 400 ( 3s elapsed / 2h 12m 51s left ) -> ETA: Thu Apr 24 17:19 XS = 2.56468941296 pb +- ( 1.60213126861 pb = 62 % ) Event 500 ( 3s elapsed / 1h 59m 36s left ) -> ETA: Thu Apr 24 17:05 XS = 2.69836107041 pb +- ( 1.32374130745 pb = 49 % ) Event 600 ( 3s elapsed / 1h 50m 46s left ) -> ETA: Thu Apr 24 16:56 XS = 2.51018495212 pb +- ( 1.99802285005 pb = 79 % ) Event 700 ( 4s elapsed / 1h 43m 44s left ) -> ETA: Thu Apr 24 16:49 XS = 2.57822312837 pb +- ( 1.72117943889 pb = 66 % ) Event 800 ( 4s elapsed / 1h 38m 27s left ) -> ETA: Thu Apr 24 16:44 XS = 3.84403029704 pb +- ( 1.6625913451 pb = 43 % ) Event 900 ( 5s elapsed / 1h 34m 21s left ) -> ETA: Thu Apr 24 16:40 XS = 3.54863526079 pb +- ( 1.47536966571 pb = 41 % ) Event 1000 ( 5s elapsed / 1h 30m 54s left ) -> ETA: Thu Apr 24 16:37 XS = 3.09399272293 pb +- ( 1.3461620323 pb = 43 % ) Event 2000 ( 9s elapsed / 1h 17m 25s left ) -> ETA: Thu Apr 24 16:23 XS = 2.39304088602 pb +- ( 2.28273401616 pb = 95 % ) Event 3000 ( 13s elapsed / 1h 12m 36s left ) -> ETA: Thu Apr 24 16:18 XS = 6.54853635522 pb +- ( 2.26060357495 pb = 34 % ) Event 4000 ( 17s elapsed / 1h 12m 35s left ) -> ETA: Thu Apr 24 16:19 XS = 5.50073474381 pb +- ( 1.72108749028 pb = 31 % ) Event 5000 ( 21s elapsed / 1h 10m 50s left ) -> ETA: Thu Apr 24 16:17 XS = 5.6303071599 pb +- ( 1.41396343905 pb = 25 % ) Event 6000 ( 25s elapsed / 1h 9m 14s left ) -> ETA: Thu Apr 24 16:15 XS = 6.06097660257 pb +- ( 1.36532286638 pb = 22 % ) Event 7000 ( 29s elapsed / 1h 8m 46s left ) -> ETA: Thu Apr 24 16:15 XS = 5.62301005466 pb +- ( 1.19859320771 pb = 21 % ) Event 8000 ( 32s elapsed / 1h 7m 44s left ) -> ETA: Thu Apr 24 16:14 XS = 5.36860027761 pb +- ( 1.06416544837 pb = 19 % ) Event 9000 ( 36s elapsed / 1h 7m 1s left ) -> ETA: Thu Apr 24 16:13 XS = 5.51828862656 pb +- ( 0.966499047828 pb = 17 % ) Event 10000 ( 40s elapsed / 1h 6m 35s left ) -> ETA: Thu Apr 24 16:13 XS = 5.44617961294 pb +- ( 0.911322457501 pb = 16 % ) Event 20000 ( 1m 17s elapsed / 1h 3m 34s left ) -> ETA: Thu Apr 24 16:11 XS = 5.28500507358 pb +- ( 1.04875927209 pb = 19 % ) Event 30000 ( 1m 55s elapsed / 1h 2m 10s left ) -> ETA: Thu Apr 24 16:10 XS = 5.31278672867 pb +- ( 0.737727750848 pb = 13 % ) Event 40000 ( 2m 33s elapsed / 1h 1m 19s left ) -> ETA: Thu Apr 24 16:10 XS = 4.5163736924 pb +- ( 0.975418064893 pb = 21 % ) Event 50000 ( 3m 10s elapsed / 1h 27s left ) -> ETA: Thu Apr 24 16:09 XS = 4.53335209372 pb +- ( 0.834751500251 pb = 18 % ) Event 60000 ( 3m 48s elapsed / 59m 44s left ) -> ETA: Thu Apr 24 16:09 XS = 4.83313636947 pb +- ( 0.710845282325 pb = 14 % ) Event 70000 ( 4m 26s elapsed / 59m 1s left ) -> ETA: Thu Apr 24 16:09 XS = 4.92861366088 pb +- ( 0.62128426052 pb = 12 % ) Event 80000 ( 5m 4s elapsed / 58m 17s left ) -> ETA: Thu Apr 24 16:09 XS = 5.14125185872 pb +- ( 0.548946078032 pb = 10 % ) Blob_List::FourMomentumConservation throws four momentum error for Shower : (-0.104192639489,0.00275502813368,0.00349892173818,0.138817745778) (1) Event 90000 ( 5m 41s elapsed / 57m 35s left ) -> ETA: Thu Apr 24 16:09 XS = 5.01096940367 pb +- ( 0.505788674971 pb = 10 % ) Event 100000 ( 6m 19s elapsed / 56m 54s left ) -> ETA: Thu Apr 24 16:09 XS = 5.05007068806 pb +- ( 0.469226055022 pb = 9 % ) Event_Handler::GenerateStandardPerturbativeEvent:("Invalid weight w=nan. Rejecting event.") Event 200000 ( 12m 55s elapsed / 51m 41s left ) -> ETA: Thu Apr 24 16:10 XS = 5.98285873407 pb +- ( 0.41691745344 pb = 6 % ) Event_Handler::GenerateStandardPerturbativeEvent:("Invalid weight w=nan. Rejecting event.") Event 300000 ( 19m 52s elapsed / 46m 23s left ) -> ETA: Thu Apr 24 16:12 XS = 6.07513386159 pb +- ( 0.318246425581 pb = 5 % ) Event 400000 ( 26m 51s elapsed / 40m 17s left ) -> ETA: Thu Apr 24 16:13 XS = 6.72942038317 pb +- ( 0.695987394177 pb = 10 % ) Event 500000 ( 33m 49s elapsed / 33m 49s left ) -> ETA: Thu Apr 24 16:13 XS = 6.59977548785 pb +- ( 0.561768242877 pb = 8 % ) Event_Handler::GenerateStandardPerturbativeEvent:("Invalid weight w=nan. Rejecting event.") Event 600000 ( 40m 46s elapsed / 27m 11s left ) -> ETA: Thu Apr 24 16:14 XS = 6.35317980822 pb +- ( 0.487881997813 pb = 7 % ) Event_Handler::GenerateStandardPerturbativeEvent:("Invalid weight w=nan. Rejecting event.") Event_Handler::GenerateStandardPerturbativeEvent:("Invalid weight w=nan. Rejecting event.") Event 700000 ( 47m 44s elapsed / 20m 27s left ) -> ETA: Thu Apr 24 16:14 XS = 6.22534145091 pb +- ( 0.420851171497 pb = 6 % ) Event 800000 ( 54m 31s elapsed / 13m 37s left ) -> ETA: Thu Apr 24 16:14  Memory usage increased by 18 MB, now 328 MB.  This might indicate a memory leak! Please monitor this process closely. XS = 6.15191144764 pb +- ( 0.369858898933 pb = 6 % ) Event_Handler::GenerateStandardPerturbativeEvent:("Invalid weight w=nan. Rejecting event.") Event 900000 ( 1h 1m 18s elapsed / 6m 48s left ) -> ETA: Thu Apr 24 16:14 XS = 6.12099146898 pb +- ( 0.330846405218 pb = 5 % ) Event_Handler::GenerateStandardPerturbativeEvent:("Invalid weight w=nan. Rejecting event.") Event 1000000 ( 4086 s total ) = 21143977.2702 evts/day Summarizing the run may take some time ... ┌────────────────────────────────────────────────────────────────────────────┐ │ Nominal or variation name XS [pb] RelDev AbsErr [pb] RelErr │ ├────────────────────────────────────────────────────────────────────────────┤ │ Nominal  6.35881 0 % 0.37078 5.83 % │ │ ME & PS: MUF=0.5  6.18115 -2.79 % 0.396143 6.4 % │ │ ME & PS: MUF=2  6.32533 -0.52 % 0.36743 5.8 % │ │ ME & PS: MUR=0.5  6.25795 -1.58 % 0.422338 6.74 % │ │ ME & PS: MUR=0.5 MUF=0.5  6.27491 -1.31 % 0.439691 7 % │ │ ME & PS: MUR=2  6.29712 -0.97 % 0.334159 5.3 % │ │ ME & PS: MUR=2 MUF=2  6.26217 -1.51 % 0.331453 5.29 % │ │ ME-only: MUF=0.5  6.33517 -0.37 % 0.378156 5.96 % │ │ ME-only: MUF=2  6.37718 0.28 % 0.362405 5.68 % │ │ ME-only: MUR=0.5  6.42404 1.02 % 0.414449 6.45 % │ │ ME-only: MUR=0.5 MUF=0.5  6.409 0.78 % 0.423205 6.6 % │ │ ME-only: MUR=2  6.29024 -1.07 % 0.335282 5.33 % │ │ ME-only: MUR=2 MUF=2  6.31331 -0.71 % 0.328076 5.19 % │ └────────────────────────────────────────────────────────────────────────────┘ Event generation statistics: Generated events: 1000000 New events: From "Beam_Remnants:Parametrised": 747 (1000754) -> 0 % From "Jet_Evolution:CSS": 2354 (1003108) -> 0.2 % Reweighting statistics: MCatNLO different PDF cut-off: 7027030 MCatNLO large PDF reweighting factor: 90626 MCatNLOvetoed large reweighting factor for parton: 178 different PDF cut-off: 26635282 large AlphaS reweighting factor: 2506445 large PDF reweighting factor: 1246064 vetoed large reweighting factor for parton: 12 Momentum fail statistics: Shower : 1 fails Error messages from 'GaugeTest' exceeded frequency limit: 129/20 Perturbative Interface (Matrix Elements): momentum failures: 113 amplitude failures: 2240 WARNING: You are using an unsupported development branch. ┌──────────────────────────────────────────────────────────┐ │ Please cite the publications listed in 'References.tex'. │ └──────────────────────────────────────────────────────────┘ Time: 1h 8m 18s on Thu Apr 24 16:14:15 2025 (User: 1h 7m 31s, System: 2s, Children User: 0s, Children System: 0s)