70 research outputs found
Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments
The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0) is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed
Search for a light Higgs resonance in radiative decays of the (1S) with a charm tag
A search is presented for the decay (1S)→γA0, A0→cc¯, where A0 is a candidate for the CP-odd Higgs boson of the next-to-minimal supersymmetric standard model. The search is based on data collected with the BABAR detector at the (2S) resonance. A sample of (1S) mesons is selected via the decay (2S)→π+π-(1S). The A0→cc¯ decay is identified through the reconstruction of hadronic D0, D+, and D∗(2010)+ meson decays. No significant signal is observed. The measured 90% confidence-level upper limits on the product branching fraction B((1S)→γA0)×B(A0→cc¯) range from 7.4×10-5 to 2.4×10-3 for A0 masses from 4.00 to 8.95GeV/c2 and 9.10 to 9.25GeV/c2, where the region between 8.95 and 9.10GeV/c2 is excluded because of background from (2S)→γχbJ(1P), χbJ(1P)→γ(1S) decays
Angular distributions in the decay B -> K*l(+)l(-)
We use a sample of 384 million BBbar events collected with the Babar detector at the PEP-II e+e- collider to study angular distributions in the rare decays B -> K* l+l-, where l+l- is either e+e- or mu+mu-. For low dilepton invariant masses, m(l+l-)3.2$ GeV/c^2, we measure AFB=0.76 (+0.52,-0.32) +/- 0.07 FL=0.71 (+0.20,-0.22) +/- 0.04.We are grateful for the excellent luminosity and machine
conditions provided by our PEP-II colleagues, and
for the substantial dedicated effort from the computing
organizations that support BABAR. The collaborating
institutions wish to thank SLAC for its support and
kind hospitality. This work is supported by DOE and
NSF (USA), NSERC (Canada), CEA and CNRS-IN2P3
(France), BMBF and DFG (Germany), INFN (Italy),
FOM (The Netherlands), NFR (Norway), MES (Russia),
MEC (Spain), and STFC (United Kingdom). Individuals
have received support from the Marie Curie EIF (European
Union) and the A. P. Sloan Foundation.Peer reviewe
Measurements of the B -> D-* form factors using the decay (B)over-bar(0)-> D(*+)e(-)(v)over-bar(e)
We measure the dependence of (B) over bar (0)-> D(*+)e(-)(B) over bar (e) on the decay angles and momentum transfer. The data sample consists of similar to 86x10(6) B (B) over bar -pairs accumulated on the Upsilon(4S) resonance by the BABAR detector at the asymmetric e(+)e(-) collider PEP-II. We specify the three form factors by two ratios R-1 and R-2, and by a single parameter rho(2) characterizing the polynomial representing h(A1), the function which describes the momentum-transfer dependence of the form factor A(1). We determine R-1, R-2, and rho(2) using an unbinned maximum likelihood fit to the full decay distribution. The results are R-1=1.396 +/- 0.060 +/- 0.035 +/- 0.027, R-2=0.885 +/- 0.040 +/- 0.022 +/- 0.013, and rho(2)=1.145 +/- 0.059 +/- 0.030 +/- 0.035. The stated uncertainties are the statistical from the data, statistical from the size of the Monte Carlo sample and the systematic uncertainty, respectively. In addition, based on this measurement, we give an updated value for the CKM matrix element vertical bar V-cb vertical bar
Observation of B→D(*) π+π−ℓ−νbar Decays in e+e- Collisions at the Υ(4S) Resonance
We report on measurements of the decays of Bbar mesons into the semileptonic final states Bbar-->D(*)pi+pi-l-nubar, where D(*) represents a D or D* meson and l- is an electron or a muon. These measurements are based on 471x10^6 BBbar pairs recorded with the BABAR detector at the SLAC asymmetric B factory PEP-II. We determine the branching fraction ratios R_pi+pi-(*)=B(Bbar-->D(*)pi+pi-l-nubar)/B(Bbar-->D(*)l-nubar) using events in which the second B meson is fully reconstructed. We find Rpi+pi-=0.067±0.010±0.008 and Rpi+pi-=0.019±0.005±0.004, where the first uncertainty is statistical and the second is systematic. Based on these results and assuming isospin invariance, we estimate that Bbar-->D(*)pipil-nubar decays, where pi denotes either a pi± and pi0 meson, account for up to half the difference between the measured inclusive semileptonic branching fraction to charm hadrons and the corresponding sum of previously measured exclusive branching fractions
CUORE and CUORE-0 experiments
Neutrino oscillation experiments proved that neutrinos have mass and this enhanced the interest in neutrinoless double-beta decay (0vββ). The observation of this very rare hypothetical decay would prove the leptonic number violation and would give us indications about neutrinos mass hierarchy and absolute mass scale. CUORE (Cryogenic Underground Observatory for Rare Events) is an array of 988 crystals of TeO2, for a total sensitive mass of 741 kg. Its goal is the observation of 0vββ of 130Te. The crystals, placed into the a dilution cryostat, are operated as bolometers at a temperature close to 10 mK. CUORE commissioning phase has been concluded recently in Gran Sasso National Laboratory, Italy, and data taking is expected to start in spring 2017. If target background rate is reached (0.01counts/day/keV/kg), the sensibility of CUORE will be, in five years of data taking, T1/21026years (1θ CL). In order to test the quality of materials and optimize the construction procedures, the collaboration realized CUORE-0, that took data from spring of 2013 to summer 2015. Here, after a brief description of CUORE, I report its commissioning status and CUORE-0 results
Search for Long-Lived Particles in e(+)e(-) Collisions
We present a search for a neutral, long-lived particle L that is produced in e+e− collisions and decays at a significant distance from the e+e− interaction point into various flavor combinations of two oppositely charged tracks. The analysis uses an e+e− data sample with a luminosity of 489.1 fb−1 collected by the BABAR detector at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and just below the ϒ(4S). Fitting the two-track mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the L production cross section, branching fraction, and reconstruction efficiency for six possible two-body L decay modes as a function of the L mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction ℬ(B→XsL), where Xs is a strange hadronic system
Search for Long-Lived Particles in e(+)e(-) Collisions
We present a search for a neutral, long-lived particle L that is produced in e(+)e(-)collisions and decays at a significant distance from the e(+)e(-) interaction point into various flavor combinations of two oppositely charged tracks. The analysis uses an e(+)e(-) data sample with a luminosity of 489.1 fb(-1) collected by the BABAR detector at the Upsilon(4S), Upsilon(3S), and Upsilon(2S) resonances and just below the Upsilon(4S). Fitting the two-track mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the L production cross section, branching fraction, and reconstruction efficiency for six possible two-body L decay modes as a function of the L mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction B(B -> XsL), where X-s is a strange hadronic system
Dalitz plot analyses of B-0 -> (D-DK+)-K-0 and B+-> (D)over-bar(-)D(0)K(+) decays
We present Dalitz plot analyses for the decays of B mesons to D−D0K+ and D¯0D0K+. We report the observation of the D∗s1(2700)+ resonance in these two channels and obtain measurements of the mass M(D∗s1(2700)+)=2699+14−7 MeV/c2 and of the width Γ(D∗s1(2700)+)=127+24−19 MeV, including statistical and systematic uncertainties. In addition, we observe an enhancement in the D0K+ invariant mass around 2350–2500 MeV/c2 in both decays B0→D−D0K+ and B+→D¯0D0K+, which we are not able to interpret. The results are based on 429 fb−1 of data containing 471×106BB¯ pairs collected at the ϒ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory
Precision measurement of the e(+)e(-) -> K+K-(gamma) cross section with the initial-state radiation method at BABAR
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