CP Sensitivity Research Articles

Synergy between DUNE and T2HKK to probe invisible neutrino decay

We address the consequence of invisible neutrino decay within the framework of two long base-line neutrino experiments: T2HKK (Tokai-to-Hyper-Kamiokande-to-Korea) and DUNE (Deep Underground Neutrino experiment). Our primary objective is to bring out the aspects of CC (charged current) and NC (neutral current) measurements at DUNE in the context of invisible neutrino decay. We find that the inclusion of NC measurements with the CC measurements enhances its ability to constrain invisible neutrino decay. Further, the synergy between DUNE and T2HKK improves the constraints on invisible neutrino decay. At 3σ C.L. (confidence level) the derived constraint is τ3/m3 ≥ 6.21 × 10−11 s/eV. Additionally, if nature prefers ν3 to be unstable and the decay width is τ3/m3 = 2.2 × 10−11 s/eV, this combination can exclude the no-decay scenario at more than 5σ C.L. Although the CP sensitivity is not much hindered in the presence of invisible neutrino decay, the measurements of θ23 and the ability to resolve octant of θ23 is significantly influenced in these individual experiments. In the presence of invisible neutrino decay, the synergy between DUNE and T2HKK can exclude the wrong octant somewhat more effectively than either experiment alone.

Study of nonstandard interactions mediated by a scalar field at the ESSnuSB experiment

In this paper, we study scalar mediator induced nonstandard interactions (SNSIs) in the context of the ESSnuSB experiment. In particular, we study the capability of ESSnuSB to put bounds on the SNSI parameters and also study the impact of SNSIs in the measurement of the leptonic CP phase δCP. Existence of SNSIs modifies the neutrino mass matrix and this modification can be expressed in terms of three diagonal real parameters (ηee, ημμ, and ηττ) and three off-diagonal complex parameters (ηeμ, ηeτ, and ημτ). Our study shows that the upper bounds on the parameters ημμ and ηττ depend upon how Δm312 is minimized in the theory. However, this is not the case when one tries to measure the impact of SNSIs on δCP. Further, we show that the CP sensitivity of ESSnuSB can be completely lost for certain values of ηee and ημτ for which the appearance channel probability becomes independent of δCP. Published by the American Physical Society 2024

Feasibility study of CP violation in decays at the Super Tau Charm Facility * *Supported by the Double First-Class university project foundation of USTC, USTC Research Funds of the Double First-Class Initiative YD2030002005 and the National Natural Science Foundation of China (11625523). The author XWK is supported by the National Natural Science Foundation of China (11805012) and the Fundamental Research

We report a feasibility study for violation in decays at a Super Tau Charm Facility (STCF). With an expected luminosity of 1 ab collected by STCF per year at a center-of-mass energy of 4.26 GeV, the statistical sensitivity for CP violation is determined to be of order by measuring the decay-rate difference between and . The analysis is performed using a reliable fast simulation software package, which can describe the detector responses properly and vary the responses flexibly for further optimization. Moreover, the energy-dependent efficiencies for reconstructing are presented. The expected CP sensitivity is proportional to in the energy region from 4.0 to 5.0 GeV. The sensitivity of CP violation is of order with 10 ab integrated luminosity, which is equivalent to ten years' data taking in this energy region at STCF.

Nuclear Effects and CP Sensitivity at DUNE

The precise measurement of neutrino-oscillation parameters is one of the highest priorities in neutrino-oscillation physics. To achieve the desired precision, it is necessary to reduce the systematic uncertainties related to neutrino energy reconstruction. An error in energy reconstruction is propagated to all the oscillation parameters; hence, a careful estimation of the neutrino energy is required. To increase the statistics, neutrino-oscillation experiments use heavy nuclear targets like argon (Z=18). The use of these nuclear targets introduces nuclear effects that severely impact the neutrino energy reconstruction which in turn poses influence in the determination of neutrino-oscillation parameters. In this work, we have tried to quantify the presence of nuclear effects on the bounds of the CP phase by DUNE using final state interactions.

A comparative study between ESSnuSB and T2HK in determining the leptonic CP phase

In this paper, we perform a comparative analysis between the future proposed long-baseline experiments ESSnuSB and T2HK in measuring the leptonic CP phase [Formula: see text]. In particular, we study the effect of the neutrino mass ordering degeneracy and the leptonic mixing angle [Formula: see text] octant degeneracy in the measurement of leptonic CP violation and precision for both experiments. Since the ESSnuSB (T2HK) experiment probes the second (first) oscillation maximum to study neutrino oscillations, the effect of these degeneracies are significantly different in both experiments. Our main conclusion is that for the ESSnuSB experiment, the information on the neutrino mass ordering does not play a major role in the determination of [Formula: see text], which is not the case for the T2HK experiment. However, the information on the true octant compromises the CP sensitivity of the ESSnuSB experiment as compared to T2HK if [Formula: see text] lies in the lower octant. These conclusions are true for both the 540 km and 360 km baseline options for the ESSnuSB experiment. In addition, we investigate the effect of different running times in neutrino and antineutrino modes and the effect of [Formula: see text] precision in measuring [Formula: see text].

Challenges posed by non-standard neutrino interactions in the determination of δCP at DUNE

One of the primary objectives of the Deep Underground Neutrino Experiment (DUNE) is to discover the leptonic CP violation and to identify its source. In this context, we study the impact of non-standard neutrino interactions (NSIs) on observing the CP violation signal at DUNE. We explore the impact of various parameter degeneracies introduced by non-zero NSI and identify which of these can influence the CP violation sensitivity and CP precision of DUNE, by considering NSI both in data and in theory. In particular, we study how the CP sensitivity of DUNE is affected because of the intrinsic hierarchy degeneracy which occurs when the diagonal NSI parameter ϵee=−1 and δCP=±90°.

Status of neutrino oscillations 2018: 3σ hint for normal mass ordering and improved CP sensitivity

We present a new global fit of neutrino oscillation parameters within the simplest three-neutrino picture, including new data which appeared since our previous analysis [1]. In this update we include new long-baseline neutrino data involving the antineutrino channel in T2K, as well as new data in the neutrino channel, data from NOνA, as well as new reactor data, such as the Daya Bay 1230 days electron antineutrino disappearance spectrum data and the 1500 live days prompt spectrum from RENO, as well as new Double Chooz data. We also include atmospheric neutrino data from the IceCube DeepCore and ANTARES neutrino telescopes and from Super-Kamiokande. Finally, we also update our solar oscillation analysis by including the 2055-day day/night spectrum from the fourth phase of the Super-Kamiokande experiment. With the new data we find a preference for the atmospheric angle in the upper octant for both neutrino mass orderings, with maximal mixing allowed at Δχ2=1.6(3.2) for normal (inverted) ordering. We also obtain a strong preference for values of the CP phase δ in the range [π,2π], excluding values close to π/2 at more than 4σ. More remarkably, our global analysis shows a hint in favor of the normal mass ordering over the inverted one at more than 3σ. We discuss in detail the status of the mass ordering, CP violation and octant sensitivities, analyzing the interplay among the different neutrino data samples.

Imprints of a light sterile neutrino at DUNE, T2HK, and T2HKK

We evaluate the impact of sterile neutrino oscillations in the so-called 3+1 scenario on the proposed long baseline experiment in USA and Japan. There are two proposals for the Japan experiment which are called T2HK and T2HKK. We show the impact of sterile neutrino oscillation parameters on the expected sensitivity of T2HK and T2HKK to mass hierarchy, CP violation and octant of $\theta_{23}$ and compare it against that expected in the case of standard oscillations. We add the expected ten years data from DUNE and present the combined expected sensitivity of T2HKK+DUNE to the oscillation parameters. We do a full marginalisation over the relevant parameter space and show the effect of the magnitude of the true sterile mixing angles on the physics reach of these experiments. We show that if one assumes that the source of CP violation is the standard CP phase alone in the test case, then it appears that the expected CP violation sensitivity decreases due to sterile neutrinos. However, if we give up this assumption, then the CP sensitivity could go in either direction. The impact on expected octant of $\theta_{23}$ and mass hierarchy sensitivity is shown to depend on the magnitude of the sterile mixing angles in a nontrivial way.

Probing CP violation with non-unitary mixing in long-baseline neutrino oscillation experiments: DUNE as a case study

When neutrino masses arise from the exchange of neutral heavy leptons, as in most seesaw schemes, the effective lepton mixing matrix N describing neutrino propagation is non-unitary, hence neutrinos are not exactly orthonormal. New CP violation phases appear in N that could be confused with the standard phase characterizing the three neutrino paradigm. We study the potential of the long-baseline neutrino experiment DUNE in probing CP violation induced by the standard CP phase in the presence of non-unitarity. In order to accomplish this we develop our previous formalism, so as to take into account the neutrino interactions with the medium, important in long baseline experiments such as DUNE. We find that the expected CP sensitivity of DUNE is somewhat degraded with respect to that characterizing the standard unitary case. However the effect is weaker than might have been expected thanks mainly to the wide neutrino beam. We also investigate the sensitivity of DUNE to the parameters characterizing non-unitarity. In this case we find that there is no improvement expected with respect to the current situation, unless the near detector setup is revamped.

Non-standard interactions and the CP phase measurements in neutrino oscillations at low energies

We study the effects of non-standard interactions (NSI) and the genuine CP phase $\delta_D$ in neutrino oscillations at low, $E_\nu \lesssim 1\,\mbox{GeV}$, and very low, $E_\nu \lesssim 0.1\,\mbox{GeV}$, energies. For experimental setup with baseline and neutrino energy tuned to the first 1-3 oscillation maximum, we develop a simple analytic formalism to show the effects of NSI. The vacuum mimicking and its violation as well as the use of the separation basis play a central role in our formalism. The NSI corrections that affect the CP phase measurement mainly come from the violation of vacuum mimicking as well as from the corrections to the 1-3 mixing angle and mass-squared difference. We find that the total NSI correction to the $\nu_\mu - \nu_e$ probability $P_{\mu e}$ can reach $20\% - 30\%$ ($1 \sigma$) at T2(H)K. Correspondingly, the correction to the CP phase can be as large as $50^\circ$ and hence significantly deteriorates the CP sensitivity at T2(H)K. The proposed TNT2K experiment, a combination of T2(H)K and the short baseline experiment $\mu$Kam that uses the Super-K/Hyper-K detector at Kamioka to measure the oscillation of the antineutrinos from muon decay at rest ($\mu$DAR), can substantially reduce the degeneracy between NSI and the genuine CP phase $\delta_D$ to provide high CP sensitivity. The NSI correction to $P_{\mu e}$ is only $2\%$ ($1 \sigma$) for $\mu$DAR neutrinos.

The physics of antineutrinos in DUNE and determination of octant and δCP

The octant of the leptonic mixing angle θ23 and the CP phase δCP are the two major unknowns (apart from neutrino mass hierarchy) in neutrino oscillation physics. It is well known that the precise determination of octant and δCP is interlinked through the octant-δCP degeneracy. In this paper we study the proficiency of the DUNE experiment to determine these parameters scrutinizing, in particular, the role played by the antineutrinos, the broadband nature of the beam and the matter effect. It is well known that for Pμe and Pμ¯e¯ the octant-δCP degeneracy occurs at different values of δCP, combination of neutrino and antineutrino runs help to resolve this. However, in regions where neutrinos do not have octant degeneracy adding antineutrino data is expected to decrease the sensitivity because of the degeneracy and reduced statistics. However we find that in case of DUNE baseline, the antineutrino runs help even in parameter space where the antineutrino probabilities suffer from degeneracies. We explore this point in detail and point out that this happens because of the (i) broad-band nature of the beam so that even if there is degeneracy at a particular energy bin, over the whole spectrum the degeneracy may not be there; (ii) the enhanced matter effect due to the comparatively longer baseline which creates an increased tension between the neutrino and the antineutrino probabilities which raises the overall χ2 in case of combined runs. This feature is more prominent for IH since the antineutrino probabilities in this case are much higher than the neutrino probabilities due to matter effects. The main role of antineutrinos in enhancing CP sensitivity is their ability to remove the octant-δCP degeneracy. However even if one assumes octant to be known the addition of antineutrinos can give enhanced CP sensitivity in some parameter regions due to the tension between the neutrino and antineutrino χ2s.

Reason for T2K to run in dominant neutrino mode for detectingCPviolation

The long-baseline experiment T2K in Japan has collected data in the neutrino mode corresponding to an exposure of $6.57 \times 10^{20}$ POT (Protons on Target) and currently it is running in the antineutrino mode. The main aim of the antineutrino run is to measure the leptonic phase $\delta_{CP}$ which may help to understand the matter-antimatter asymmetry of the universe. In this work we show that in T2K, antineutrinos are required only for removing the wrong octant solutions which in turn improves the CP sensitivity. If however the octant is known then pure neutrino run is capable of giving the maximum CP sensitivity. If we divide the total true parameter space into eight sets, then we find that T2K antineutrino run helps in improving the CP sensitivity for only two sets while for the remaining six combinations pure neutrino run gives the best CP sensitivity. Thus if the neutrino run is replaced by the antineutrino run then it causes a reduction in the CP sensitivity in 75$\%$ of the true parameter space due to lesser statistics. Thus it is worthwhile to study if the T2K antineutrino run can be reduced by the antineutrino runs of the other experiments, so that T2K can run in dominant neutrino mode to extract the best CP sensitivity. In this work we explore the possibility of the antineutrino component of NO$\nu$A and the atmospheric neutrino experiment ICAL@INO for compensating the antineutrino run of T2K.

Differentiation between high-grade gliomas and metastatic brain tumors using Diffusion Tensor Imaging metrics

IntroductionThe aim of this work was to differentiate between high-grade gliomas and metastatic brain tumors using diffusion tensor derived metrics in the enhancing tumor and peri-tumoral regions. Patients & methodsProspective study was done on 36 patients with provisional MRI diagnosis of high grade gliomas WHO grade III & IV versus metastatic brain tumors, examination was done on 1.5tesla scanner, patients were divided into two groups based on pathology results, the fraction anisotropy (FA), mean diffusivity (MD), linear coefficient (CL), planer coefficient (CP) and spherical coefficient (CS) were measured in the enhancing tumor parts and immediate peri-tumoral edema and results were compared between the two groups. ResultsValues of FA, CL and CP measured in the peri-tumoral edema were significantly high in the metastatic than primary high malignant glial tumors with high specificity (100%) of the CP and high sensitivity of the CL (76.5%) among the three significant values, and no significant differences in the values of MD and CS. The values of the five metrics measured in the enhancing tumor parts showed no significant differences between the two groups. ConclusionBrain metastasis and high-grade gliomas can be differentiated using DTI derived FA, CL and CP measured in the peri-tumoral region.

What can we learn about the lepton CP phase in the next 10 years?

We discuss how the lepton CP phase can be constrained by accelerator and reactor measurements in an era without dedicated experiments for CP violation search. To characterize globally the sensitivity to the CP phase \delta_{CP}, we introduce a new measure, the CP exclusion fraction, which quantifies what fraction of the \delta_{CP} space can be excluded at a given input values of \theta_{23} and \delta_{CP}. Using the measure we study the CP sensitivity which may be possessed by the accelerator experiments T2K and NOvA. We show that, if the mass hierarchy is known, T2K and NOvA alone may exclude, respectively, about 50%-60% and 40%-50% of the \delta_{CP} space at 90% CL by 10 years running, provided that a considerable fraction of beam time is devoted to the antineutrino run. The synergy between T2K and NOvA is remarkable, leading to the determination of the mass hierarchy through CP sensitivity at the same CL.

Evidence for leptonic CP phase from NOνA, T2K and ICAL: A chronological progression

We study the synergy between the long-baseline (LBL) experiments NOνA and T2K and the atmospheric neutrino experiment ICAL@INO for obtaining the first hint of CP violation in the lepton sector. We also discuss how precisely the leptonic CP phase (δCP) can be measured by these experiments. The CP sensitivity is first described at the level of oscillation probabilities, discussing its dependence on the parameters – θ13, mass hierarchy and θ23. In particular, we discuss how the precise knowledge or lack thereof of these parameters can affect the CP sensitivity of LBL experiments. We follow a staged approach and analyze the δCP sensitivity that can be achieved at different points of time over the next 15 years from these LBL experiments alone and/or in conjunction with ICAL@INO. We find that the CP sensitivity of NOνA/T2K is enhanced due to the synergies between the different channels and between the two experiments. On the other hand the lack of knowledge of hierarchy and octant makes the CP sensitivity poorer for some parameter ranges. Addition of ICAL data to T2K and NOνA can exclude these spurious wrong-hierarchy and/or wrong-octant solutions and cause a significant increase in the range of δCP values for which a hint of CP violation can be achieved. In fact in parameter regions unfavourable for NOνA/T2K, we may get the first evidence of CP violation by adding the ICAL data to these. Similarly the precision with which δCP can be measured also improves with inclusion of ICAL data.

Abstract 4525: Targeting ROS to kill cisplatin-resistant cells

Abstract Cisplatin (CP) resistance remains a major problem in the treatment of both small cell and non small cell lung cancer. We have previously shown that inhibiting mTOR can restore CP sensitivity; however, not all CP resistant cell lines are sensitive to mTOR inhibitor. Our findings have led us to search for an alternative target in these CP resistant cells. We have discovered that CP resistant cells share one common biochemical parameter which is increased reactive oxygen species (ROS) when compared to normal cells and their parental cells counterpart. Thus, further increased ROS in these CP resistant cells can push them beyond their tolerance limit which ultimately leads to cell death. We have found that increased expression of NADPH oxidase 4 (NOX4) and lower levels of thioredoxin (Trx) correlate with the high levels of ROS seen in CP resistant cell lines. Using elesclomol (N′1, N′3-dimethyl-N′1, N′3- bis [phenylcarbonothioyl] propanedihydrazide (formerly STA-4783, provided by Synta Pharmaceuticals)), an agent which is known to increase ROS, we demonstrated that elesclomol can increase H2O2 levels in CP resistant lung cancer cell lines (CP-R). Moreover, elesclomol is also significantly more cytotoxic toward CP-R with the ID50 dosage of 4-10 fold less than their parental cells (PC) counterpart and normal cells, BJ-1 (see table below). The percentage of apoptosis is also significantly higher in CP-R (65%) vs. PC (3%). The cytotoxic effect of elesclomol in CP-R is accompanied by further decrease in Trx and glutathione (GSH) antioxidant systems, while opposite results were found in PC and normal cells. This cytotoxic effect can be reversed by an antioxidant, N-acetylcysteine (NAC, 0.1mM). Furthermore, we have also found that elesclomol also increased intracellular CP and hence enhanced CP sensitivity in CP-R cells. We conclude that elesclomol is highly effective in CP resistant cells which express high basal levels of ROS and should be considered for treatment of CP resistant tumor.ID50 Dosage of Elesclomol in Parental (PC) vs. Cisplatin Resistant (CP-R) Lung Cancer Cell Lines SCLC1(PC)SCLCSR2(CP-R)SCLCB(PC)SCLCBC (CP-R)NSCLCS(PC)NSCLCSC(CP-R)BJ1Elesclomol(nM)50+/−2.55+/−0.541+/−3.89+/−1.259+/−4.610+/−2.265+/−5.5 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4525.

Effect of leptonic CP phase in νμ→ νμoscillations

In the case of large 1-3 mixing angle as sin^2(2theta13 > 0.03, we investigate the possibility for measuring the leptonic CP phase by using only nu_mu --> nu_mu oscillations independently of nu_mu --> nu_e oscillations. As the result, we find that the CP phase can be measured best around the energy E=0.43 GeV and the baseline length L=5000km without strongly depending on the uncertainties of other parameters. In this region, the CP phase effect remains even after averaging over neutrino energy. We also find that there is the CP sensitivity even in the short baseline length L < 1000 km if Delta m_{31}^2 is determined with the uncertainty of about 0.1 . In the T2KK experiment, we explore the possibility for determining Delta m_{31}^2 by using one baseline from Tokai to Korea and then measuring the CP phase by using the baseline to Kamioka. As the result, we find that some information of the CP phase can be obtained from both measurements.

Matter profile effect in a neutrino factory: yet another correlation in the analysis on CP violation at a neutrino oscillation experiment

We investigate the effect induced by the variation of the density profile of the Earth's interior in a long baseline neutrino oscillation experiment. We show that there is a strong correlation between the average density value and the first Fourier coefficient of the matter profile function in the analyses on the oscillation probability. We also point out two facts: the most essential part of the matter profile is the first Fourier mode of the matter profile function, and the Earth models based on the study of the seismology include large uncertainty for the first Fourier mode. This means that the matter profile effect induces extra uncertainty for average matter parameter. Taking into account this extra uncertainty, we make numerical calculations for the sensitivity to CP violation search. The results show that the CP sensitivity is impaired in large Ue3 region.

Prospects of heavy quark physics in Run II with the DØ detector

After a successful Run I, DO is poised for an encore performance in Run II. This article summarizes the essential features of the DO upgrade that involve a central magnetic field, a new tracking system, upgraded muon detection, and enhancements to muon, calorimeter and the data acquisition electronics. The goals for top quark physics for Run II are outlined along with issues affecting the precision measurement of top quark mass and single top quark production. The prospects and issues determining the B physics capabilities of DO in Run II are addressed briefly and a study of the CP sensitivity in the mode B o d → J/ψK o s is also presented.