M. Aglietta

Muon ''depth-intensity'' relation measured by the LVD underground experiment and cosmic-ray muon spectrum at sea level

We present the analysis of the muon events with all muon multiplicities collected during 21804 hours of operation of the first LVD tower. The measured angular distribution of muon intensity has been converted to the `depth -- vertical intensity relation in the depth range from 3 to 12 km w.e.. The analysis of this relation allowed to derive the power index,

The large-volume detector (LVD) of the Gran Sasso Laboratory

gamma

Study of the effect of neutrino oscillations on the supernova neutrino signal in the LVD detector

, of the primary all-nucleon spectrum:

Upper limit on the prompt muon flux derived from the LVD underground experiment

gamma=2.78 pm 0.05

Study of single muons with the Large Volume Detector at the Gran Sasso Laboratory

. The `depth -- vertical intensity relation has been converted to standard rock and the comparison with the data of other experiments has been done. We present also the derived vertical muon spectrum at sea level.

First CNGS events detected by LVD

SummaryWe describe here the LVD experiment (Large-Volume Detector) of the Gran Sasso Laboratory, which is the natural improvement of the LSD experiment (Liquid Scintillation Detector) running in the Mont Blanc Laboratory. The LVD ((31×13) m2 area, height 12 m) consists of ≈1800 tons of liquid scintillator and of a system of streamer tubes on 5 layers for reconstructing tracks of charged particles. As any experiment in an underground laboratory, which has a low statistics of events and requires long running times, the LVD is a multipurpose experiment but with different priorities of the researches. The main goal is neutrino astronomy, firstly detection of neutrinos from collapsing stars and secondly high-energy neutrinos and solar neutrinos. Since the expected number of interactions of neutrinos, from a stellar collapse is very high (of order of 900 for a collapse at the distance of the galactic centre), the LVD is, contrary to the present experiments, a real neutrino observatory, able to make a detailed analysis of the energy and temporal distributions of the burst. In addition to neutrino astrophysics, with the LVD experiment excellent possibilities exist to perform researches in cosmic-ray and high-energy elementary-particle physics.RiassuntoSi descrive lesperimento LVD (Large Volume Detector) del laboratorio del Gran Sasso, che rappresenta il naturale sviluppo dellesperimento LSD (Liquid Scintillation Detector) in funzione nel laboratorio del Monte Bianco. LVD (area (31×13) m2, altezza 12 m) consiste di ∼1800 tonnellate di scintillatore liquido e di un sistema di tubi a streamer su 5 piani per la ricostruzione delle tracce di particelle cariche. Come tutti gli esperimenti in laboratori sotterranei, che sono a tempi lunghi ed a bassa statistica, lesperimento LVD è a multiscopi ma con diverse priorità delle ricerche. Lobiettivo principale è lastronomia neutrinica, in primo luogo la rivelazione di neutrini da collassi gravitazionali stellari, e poi neutrini di alta energia e neutrini solari. Dato lalto numero previsto di interazioni di neutrini (∼900 per un collasso alla distanza del centro galattico) da stelle collassanti, lesperimento LVD costituisce, a differenza degli attuali esperimenti, un vero e proprio osservatorio neutrinico, in grado di compiere unanalisi dettagliata delle distribuzioni energetica e temporale del burst. Oltre allastrofisica neutrinica, con lesperimento LVD si possono compiere ricerche in fisica della radiazione cosmica e di particelle elementari ad altissime energie.РезюмеВ данной работе описывается зксперимент LVD (Large Volume Detector), который будет проводиться в лаборатории Гран Cacco. LVD является естественным продолжением эксперимента LSD (Liquid Scintillation Detector) в лаборатории Монблан. LVD (площадь (31×13) м2, высота 12 м) содержит 1800 тонн жидкого сцинтиллятора и включает в себя систему стримерных детекторов, размещенных на 5 уровнях. Последние используются для реконструкции треков заряженных частиц. Как и любой длительный эксперимент в подземных условиях, когда статистика событий невелика, LVD имеет многоцелевое назначение. Научные программы, однако, будут обладать различным приоритетом. Основное внимание будет уделяться нейтринной астрономии, и в первую очередь— детектированию нейтрино от коллапсирующих звезд. Кроме того, будут проводиться исследования по регистрации нейтрино высоких энергий и солнечных нейтрино. Поскольку ожидаемое количество взаимодействий в случае прихода потока нейтрино от коллапса очень велико, порядка 900, LVD будет настоящей нейтринной обсерваторией, способной, в отличие от ведущихся сейчас экспериментов, детально исследовать энергетическое временное распределения для вспышки нейтринного излучения. В дополнение к нейтринной астрофизике, имеются очень хорошие перспективы и для исследований в области космических лучей и физики элементарных частиц высоких энергий.

Measurement of the neutron flux produced by cosmic ray muons with LVD at Gran Sasso

The LVD detector, located in the INFN Gran Sasso National Laboratory (Italy), studies supernova neutrinos through the interactions with protons and carbon nuclei in the liquid scintillator and interactions with the iron nuclei of the support structure. We investigate the effect of neutrino oscillations in the signal expected in the LVD detector. The MSW effect has been studied in detail for neutrinos travelling through the collapsing star and the Earth. We show that the expected number of events and their energy spectrum are sensitive to the oscillation parameters, in particular to the mass hierarchy and the value of

10 Years Search for Neutrino Bursts with LVD

theta_{13}

Upper limits to low energy

, presently unknown. Finally we discuss the astrophysical uncertainties, showing their importance and comparing it with the effect of neutrino oscillations on the expected signal.

\bar\nu_\mathrm{e}

We present the analysis of the muon events with all muon multiplicities collected during 21804 hours of operation of the first LVD tower. The measured depth-angular distribution of muon intensities has been used to obtain the normalization factor, A, the power index, gamma, of the primary all-nucleon spectrum and the ratio, R_c, of prompt muon flux to that of pi-mesons - the main parameters which determine the spectrum of cosmic ray muons at the sea level. The value of gamma = 2.77 +/- 0.05 (68% C.L.) and R_c<2.0 x 10^-3 (95% C.L.) have been obtained. The upper limit to the prompt muon flux favours the models of charm production based on QGSM and the dual parton model.