The neutrino mass hierarchy determination (ν MHD) is one of the main goals of the major current and future neutrino experiments. The statistical analysis usually proceeds from a standard method, a ...single-dimensional estimator 1D−Δχ2 that shows some drawbacks and concerns, together with a debatable strategy. The drawbacks and considerations of the standard method will be explained through the following three main issues. The first issue corresponds to the limited power of the standard method. The Δχ2 estimator provides us with different results when different simulation procedures were used. Regarding the second issue, when χminNH2 and χminIH2 are drawn in a 2D map, their strong positive correlation manifests χ2 as a bidimensional variable, instead of a single-dimensional estimator. The overlapping between the χ2 distributions of the two hypotheses leads to an experiment sensitivity reduction. The third issue corresponds to the robustness of the standard method. When the JUNO sensitivity is obtained using different procedures, either with Δχ2 as one-dimensional or χ2 as two-dimensional estimator, the experimental sensitivity varies with the different values of the atmospheric mass, the input parameter. We computed the oscillation of Δχ2¯ with the input parameter values, Δm2input. The MH significance using the standard method, Δχ2, strongly depends on the values of the parameter Δm2input. Consequently, the experiment sensitivity depends on the precision of the atmospheric mass. This evaluation of the standard method confirms the drawbacks.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing investigation of new physics beyond the Standard Model. The rather recent ...measurement of the third mixing angle θ13 in the standard mixing oscillation scenario encourages the pursuit of what is still missing: the size of any leptonic CP violation, absolute neutrino masses and the characteristic nature of the neutrino. Several projects are currently running and they are providing impressive results. In this review, the phenomenology of neutrino oscillations that results from the last two decades of investigations is reviewed, with emphasis on our current knowledge and on what lesson can be taken from the past. We then present a critical discussion of current studies on the mass ordering and what might be expected from future results. Our conclusion is that decisions determining the next generation of experiments and investigations have to be strictly based on the findings of the current generation of experiment. In this sense it would be wise to wait a few years before taking decisions on the future projects. In the meantime, since no direct path forward is evident for the future projects, the community must be committed to their careful evaluation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nowadays neutrino physics is undergoing a change of perspective: the discovery period is almost over and the phase of precise measurements is starting. Despite the limited statistics collected for ...some variables, the three–flavor oscillation neutrino framework is strengthening well. In this framework a new method has been developed to determine the neutrino mass ordering, one of the still unknown and most relevant parameters. The method is applied to the 2015 results of the NOvA experiment for νμ→νe appearance, including its systematic errors. A substantial gain in significance is obtained compared to the traditional Δχ2 approach. Perspectives are provided for future results obtainable by NOvA with larger exposures. Assuming the number of the 2015 νe observed events scales with the exposure, an increase in only a factor three would exclude the inverted hierarchy at more than 95% C.L. over the full range of the CP violating phase. The preliminary 2016 NOvA measurement on νμ→νe appearance has also been analyzed.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
A
bstract
The exclusive photoproduction reactions
γp
→
J/ψ
(1
S
)
p
and
γp
→
ψ
(2
S
)
p
have been measured at an
ep
centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated ...luminosity of 373 pb
−
1
. The measurement was made in the kinematic range 30
< W <
180 GeV,
Q
2
<
1 GeV
2
and |
t
|
<
1 GeV
2
, where
W
is the photon-proton centre-of-mass energy,
Q
2
is the photon virtuality and
t
is the squared four-momentum transfer at the proton vertex. The decay channels used were
J/ψ
(1
S
)
→ μ
+
μ
−
,
ψ
(2
S
)
→ μ
+
μ
−
and
ψ
(2
S
)
→ J/ψ
(1
S
)
π
+
π
−
with subsequent decay
J/ψ
(1
S
)
→ μ
+
μ
−
. The ratio of the production cross sections,
R
=
σ
ψ
(2
S
)
/σ
J/ψ
(1
S
)
, has been measured as a function of
W
and |
t
| and compared to previous data in photoproduction and deep inelastic scattering and with predictions of QCD-inspired models of exclusive vector-meson production, which are in reasonable agreement with the data.
Abstract The exclusive photoproduction reactions γp → J/ψ(1S)p and γp → ψ(2S)p have been measured at an ep centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated ...luminosity of 373 pb −1. The measurement was made in the kinematic range 30 < W < 180 GeV, Q 2 < 1 GeV2 and |t| < 1 GeV2, where W is the photon-proton centre-of-mass energy, Q 2 is the photon virtuality and t is the squared four-momentum transfer at the proton vertex. The decay channels used were J/ψ(1S) → μ + μ − , ψ(2S) → μ + μ − and ψ(2S) → J/ψ(1S)π + π − with subsequent decay J/ψ(1S) → μ + μ − . The ratio of the production cross sections, R = σ ψ(2S) /σ J/ψ(1S), has been measured as a function of W and |t| and compared to previous data in photoproduction and deep inelastic scattering and with predictions of QCD-inspired models of exclusive vector-meson production, which are in reasonable agreement with the data.
Combined HERA data on charm production in deep-inelastic scattering have previously been used to determine the charm-quark running mass mc(mc) in the MS‾ renormalisation scheme. Here, the same data ...are used as a function of the photon virtuality Q2 to evaluate the charm-quark running mass at different scales to one-loop order, in the context of a next-to-leading order QCD analysis. The scale dependence of the mass is found to be consistent with QCD expectations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The neutrino mass hierarchy determination (ν MHD) is one of the main goals of the major current and future neutrino experiments. The statistical analysis usually proceeds from a standard method, a ...single-dimensional estimator (1D-Δ χ sup.2) that shows some drawbacks and concerns, together with a debatable strategy. The drawbacks and considerations of the standard method will be explained through the following three main issues. The first issue corresponds to the limited power of the standard method. The Δ χ sup.2 estimator provides us with different results when different simulation procedures were used. Regarding the second issue, when χ min(NH)2 and χ min(IH)2 are drawn in a 2D map, their strong positive correlation manifests χ sup.2 as a bidimensional variable, instead of a single-dimensional estimator. The overlapping between the χ sup.2 distributions of the two hypotheses leads to an experiment sensitivity reduction. The third issue corresponds to the robustness of the standard method. When the JUNO sensitivity is obtained using different procedures, either with Δ χ sup.2 as one-dimensional or χ sup.2 as two-dimensional estimator, the experimental sensitivity varies with the different values of the atmospheric mass, the input parameter. We computed the oscillation of |Δ χ sup.2¯| with the input parameter values, |Δ msup.2|sub.input. The MH significance using the standard method, Δ χ sup.2, strongly depends on the values of the parameter |Δ msup.2|sub.input. Consequently, the experiment sensitivity depends on the precision of the atmospheric mass. This evaluation of the standard method confirms the drawbacks.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The neutrino mass hierarchy determination ( ν MHD) is one of the main goals of the major current and future neutrino experiments. The statistical analysis usually proceeds from a standard method, a ...single-dimensional estimator 1 D − Δ χ 2 that shows some drawbacks and concerns, together with a debatable strategy. The drawbacks and considerations of the standard method will be explained through the following three main issues. The first issue corresponds to the limited power of the standard method. The Δ χ 2 estimator provides us with different results when different simulation procedures were used. Regarding the second issue, when χ min NH 2 and χ min IH 2 are drawn in a 2D map, their strong positive correlation manifests χ 2 as a bidimensional variable, instead of a single-dimensional estimator. The overlapping between the χ 2 distributions of the two hypotheses leads to an experiment sensitivity reduction. The third issue corresponds to the robustness of the standard method. When the JUNO sensitivity is obtained using different procedures, either with Δ χ 2 as one-dimensional or χ 2 as two-dimensional estimator, the experimental sensitivity varies with the different values of the atmospheric mass, the input parameter. We computed the oscillation of Δ χ 2 ¯ with the input parameter values, Δ m 2 input . The MH significance using the standard method, Δ χ 2 , strongly depends on the values of the parameter Δ m 2 input . Consequently, the experiment sensitivity depends on the precision of the atmospheric mass. This evaluation of the standard method confirms the drawbacks.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
This article describes a design of an field-programmable gate array (FPGA) implementation of a clock and data recovery (CDR) system. The core will be integrated in the FPGA configuration for the ...front-end electronics (FEE) board of the Jiangmen underground neutrino observatory (JUNO) experiment. The front-end will be placed on the main detector, underground and underwater, making the electronics not accessible after installation. The timing and trigger system relies on a synchronous link connection over CAT5e cable (up to 100 m long) between the front-end and the back-end electronics (BEE), where a twisted-pair is dedicated to clock-forwarding. The robustness of the recovery clock system is essential for the stability of the FPGA firmware. The proposed project is intended to improve the clock recovery operation by increasing the immunity of the link to sudden electromagnetic interference (EMI). On top of this, the core allows to free a twisted-pair in the link, since the clock can be recovered from the data and there is no more need for a clock-dedicated transmission. This will optimize the link granting the possibility to implement other features. The design is based on two components: a numerically-controlled oscillator (NCO), in order to create a controlled frequency clock signal, and a digital phase detector (PD) to match the clock frequency with the data rate. NCOs are often coupled with a digital-to-analog converter (DAC) to create direct digital synthesizers (DDSs), which are able to produce analog waveforms of any desired frequency. In the presented case instead, the NCO generates a digital clock signal of an arbitrary frequency, while the PD manages this frequency by intercepting any shifting on the relative phase between the clock and the data. A phase aligner (PA) module guarantees that data are sampled in the middle of the eye pattern, which represents the optimal sampling point. The article presents an overview of the NCO-based CDR design and implementation, together with some tests and results in order to verify the CDR reliability. Moreover, in the last section, some other possible applications of the core are illustrated.
Abstract
In 1956 Reines & Cowan discovered the neutrino using a liquid scintillator detector. The neutrinos interacted with the scintillator, producing light that propagated across transparent ...volumes to surrounding photo-sensors. This approach has remained one of the most widespread and successful neutrino detection technologies used since. This article introduces a concept that breaks with the conventional paradigm of transparency by confining and collecting light near its creation point with an opaque scintillator and a dense array of optical fibres. This technique, called LiquidO, can provide high-resolution imaging to enable efficient identification of individual particles event-by-event. A natural affinity for adding dopants at high concentrations is provided by the use of an opaque medium. With these and other capabilities, the potential of our detector concept to unlock opportunities in neutrino physics is presented here, alongside the results of the first experimental validation.
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