Reply to SSC recommendations M. de Jong KM3NeT meeting Bologna, 5 October 2012

Reminder  Scientific Standing Committee (SSC) – mandate “to carry out a critical review of the KM3NeT science case for neutrino astro-particle physics and of aspects related to the design, construction, deployment, commissioning and operation of the detector.” – Report issued 18 February 2012 – Message from E. Migneco to SSC, April 2012 “... The procedure for the election of the new management with a centralised structure has started...” – Message from F. Linde (chair ASC) continuation/evolution of SSC draft report expected by end of November

Recommendations 1.The KM3NeT Consortium is urged to perform Monte Carlo optimization studies on a variety of fronts to reduce by roughly a factor of two their figure of merit... One or two additional FoMs may be warranted, in particular one for neutrino-induced showers, from a diffuse flux of extraterrestrial neutrinos. The chosen FoM(s) should be calculated for each site, assuming the same underlying detector hardware components, but with detector geometries (e.g., tower spacing and bar length) optimized for each site.

Recommendations (II) 2. a.To demonstrate the claimed superiority of the multi-PMT... b.Further studies are needed to prove the superiority of the bar tower... pairs of modules close enough to see coincidences but not so close as to see individual 40 K events...works as well. c....study ought to be with close pairs of strings to achieve the horizontal reconstruction leverage versus the bars. d....the optimization of the detector taking into account the characteristics of its site should be fully developed...

Recommendation (III) 3....recommend development and deployment of a “Demonstrator” detector... 4.The SSC recommends that the KM3NeT Consortium establish criteria and a process to clearly identify the best single site for the deployment of the full detector... 5.The SSC recommends that the Consortium evaluate accurately and quantitatively the scientific (loss of FoM) and financial (more infrastructural and running costs) consequences of using more than one site. The effects of bioluminescence...

Recommendations (IV) 6.As the various groups within KM3NeT are not cooperating in a sufficiently coherent manner, a stronger, centralized and site-neutral leadership is needed in the next phases of the project An independent scientific and technical advisory committee should be appointed by the agencies to follow all the phases of the project with continuity of committee membership sufficient to allow a coherent perspective over project lifetime “Technical Design Report”...

Recommendations (V) 9.The collaboration will need to expand The observation or non-observation by existing ongoing projects should be used to further optimize the design, especially in terms of required detection volume and sensitivity.

Project evolution  Erlangen, June 2012 – agreement that multi-PMT optical module and a string constitute base line technology  Paris, 7 July 2012 – endorsement of the agreement on base line technology by representatives of funding agencies

Actions  send to WPD12 September 2012 – request for help – 9 replies (from ECAP, HOU, LNS and Nikhef)  telephone conference26 September 2012 – minutes available  KM3NeT wide discussiontoday – more volunteers

In the following, an account of the first telephone conference on 26 September 2012 is presented.

Reply 1. Figures of Merit: – Galactic sources ¶ (improvement of the sensitivity, all); – Fermi bubbles (LNS); – Diffuse flux (LNS); – Neutrinos from cosmic ray interactions in galactic plane (Nikhef, following 3); ¶ A 5 sigma discovery potential in 3 years would make a convincing case for KM3NeT (mjg)

Reply (II) 2. a.General progress report; b.A general solution to filter the data exists and has been reported in KM3NeT internal note; c.Nothing to be done; d.The main effects to be studied are the dependencies of the detector performance on the absorption length and on the depth; study of absorption length was made and is documented (also this presentation), will be verified by Rosa et al. simulation of atmospheric muon background ‒inventory of available data (Rosa et al.) ‒Erlangen agreed to help with production of data

Reply (III) 3.General progress report. 4.The concept of a modular detector should be evaluated in terms of cost (nothing to be done) and detector performance (mostly done). The net effect on the overall figure of merit as a function of the distribution of modules between the three sites can then be formulated as a linear expression.

Reply (IV) 5.Bioluminescence data are presented in the Technical Design Report. More recent data from Antares should be collected (mjg). A document with results from a preliminary analysis of the long term autonomous measurements of singles rates in Sicily and Pylos should be circulated (mjg). 6.Outside scope 7.Outside scope 8.Postponed 9.Outside scope

Reply (V) 10.The primary physics goal of KM3NeT is the discovery of a neutrino point source in our galaxy. As such, there is no competition from IceCube (outside field of view) or other neutrino telescopes on the Northern hemisphere (limited size).

Recent updates  General solution to trigger the events ‒KM3NeT internal note by B. Bakker  Detector performance study ‒KM3NeT internal note ‒also this presentation  Figure(s) of merit ‒next presentation by P. Sapienza

Detector performance study  input – base line technology multi-PMT optical module and a string – WPD document footprint, QE, PMT angular acceptance, absorption length, scattering length, scattering angle distribution, etc.  performance indicator – number of events with ≥ 5 L1s from RXJ1713 L1 corresponds to two (or more) hits on same optical module within 10 ns  procedure – scaling factor applied to absorption length (0.9, 1.0, 1.1, 1.2) – vary horizontal spacing 80 ‒ 130 m and vertical spacing 30 ‒ 50 m – determine optimal spacing for each absorption length – dependence of performance figure on scaling factor

Module events / year number of linesnumber of floors Module = 120 strings with 18 optical modules scaling factor

Example events / year horizontal spacing [m] scaling factor 1.1 There is a clear maximum scaling factor 1.1 vertical spacing [m] vertical spacing horizontal spacing

Dependence on absorption length events / year scaling factor optimal detector There is a clear linear dependence

Summary & outlook  The input to the reply to the SSC report still requires a substantial amount of work ‒e.g. need for a good energy discriminator to improve figure of merit for galactic sources ‒need more data on atmospheric muons ‒source stacking, source morphology, etc.  The editing of the document involves sensitive information  The drafting of the document should go through some reviewing procedure, to be defined a.s.a.p.