arXiv subjects

Monojit Ghosh

Publications and source records attributed to Monojit Ghosh.

At least 37 records · Page 2Linked to original sources

arXiv2023

Effect of Matter Density in T2HK and DUNE

CP phase determination for the near future long baseline experiments, T2HK and DUNE, will require precise measurements of the oscillation probabilities. However, the uncertainty in the Earth's density must be considered in determining these oscillation probabilities. Therefore, in this study, we update the individual sensitivities of these experiments for determining the current unknowns in the standard three flavor scenario considering the latest configuration and also the complementarity between them while considering the uncertainty in the density. Our study showed that this uncertainty has a non-negligible impact on the precision of the CP phase determination particularly for DUNE.

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arXiv2023

Determining Neutrino Mass Ordering with ICAL, JUNO and T2HK

In this paper we study the synergy among the future accelerator (T2HK), future atmospheric (ICAL) and future reactor (JUNO) neutrino experiments to determine the neutrino mass ordering. T2HK can measure the mass ordering only for favorable values of $δ_{\rm CP}$, whereas the mass ordering sensitivity of JUNO is dependent on the energy resolution. Our results show that with a combination of T2HK, ICAL and JUNO one can have a mass ordering sensitivity of 7.2 $σ$ even for the unfavorable value of $δ_{\rm CP} = 0^\circ$ for T2HK and most conservative value of JUNO energy resolution of 5$\%/\sqrt{E(MeV)}$. The synergy mainly comes because different oscillation channels prefer different values of $|Δm_{31}^2|$ in the fit when the mass-ordering $χ^2$ is minimized. In this context we also study: (i) effect of varying energy resolution of JUNO, (ii) the effect of longer run-time of ICAL, (iii) effect of different true values of $θ_{23}$ and (iv) effect of octant degeneracy in the determination of neutrino mass ordering.

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arXiv2022

Neutrino Mass Ordering -- Circumventing the Challenges using Synergy between T2HK and JUNO

One of the major open problems of neutrino physics is MO (mass ordering). We discuss the prospects of measuring MO with two under-construction experiments T2HK and JUNO. JUNO alone is expected to measure MO with greater than $3σ$ significance as long as certain experimental challenges are met. In particular, JUNO needs better than 3$\%$ energy resolution for MO measurement. On the other hand, T2HK has rather poor prospects at measuring the MO, especially for certain ranges of the CP violating parameter $δ_{\rm CP}$, posing a major drawback for T2HK. In this letter we show that the synergy between JUNO and T2HK will bring two-fold advantage. Firstly, the synergy between the two experiments helps us determine the MO at a very high significance. With the baseline set-up of the two experiments, we have a greater than $9σ$ determination of the MO for all values of $δ_{\rm CP}$. Secondly, the synergy also allows us to relax the constraints on the two experiments. We show that JUNO, could perform extremely well even for energy resolution of 5$\%$, while for T2HK the MO problem with "bad" values of $δ_{\rm CP}$ goes away. The MO sensitivity for the combined analysis is expected to be greater than $6σ$ for all values of $δ_{\rm CP}$ and with just 5$\%$ energy resolution for JUNO.

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arXiv2022

Extracting the best physics sensitivity from T2HKK: A study on optimal detector volume

T2HK is an upcoming long-baseline experiment in Japan which will have two water Cherenkov detector tanks of 187 kt volume each at distance of 295 km from the source. An alternative project, T2HKK is also under consideration where one of the water tanks will be moved to Korea at a distance of 1100 km. The flux at 295 km will cover the first oscillation maximum and the flux at 1100 km will mainly cover the second oscillation maximum. As physics sensitivity at the dual baseline rely on variation in statistics, dependence of systematic uncertainty, effect of second oscillation maximum and matter density, 187 kt detector volume at 295 km and 187 kt detector volume at 1100 km may not be the optimal configuration of T2HKK. Therefore, we have tried to optimize the ratio of the detector volume at both the locations by studying the interplay between the above mentioned parameters. For the analysis of neutrino mass hierarchy, octant of $θ_{23}$ and CP precision, we have considered two values of $δ_{\rm{CP}}$ as 270$^\circ$ and $0^\circ$ and for CP violation we have considered the value of $δ_{\rm CP}= 270^\circ$. These values are motivated by the current best-fit values of this parameter as obtained from the experiments T2K and NO$ν$A. Interestingly we find that if the systematic uncertainty is negligible then the T2HK setup i.e., when both the detector tanks are placed at 295 km gives the best results in terms of hierarchy sensitivity at $δ_{\rm CP}= 270^\circ$, octant sensitivity, CP violation sensitivity and CP precision sensitivity at $δ_{\rm CP}= 0^\circ$. For current values of systematic errors, we find that neither T2HK, nor T2HKK setup is giving better results for hierarchy, CP violation and CP precision sensitivity. The optimal detector volume which is of the range between 255 kt to 345 kt at 1100 km gives better results in those above mentioned parameters.

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arXiv2022

Optimal configuration of Protvino to ORCA experiment for hierarchy and non-standard interactions

In this paper, we study the hierarchy sensitivity of Protvino to ORCA (P2O) experiment in three flavour scenario as well as its sensitivity to non-standard interactions (NSI) in neutrino propagation. Because of the largest possible baseline length of 2595 km, P2O is expected to have strong sensitivity towards neutrino mass hierarchy and NSI parameters. In our study, we show that even though the number of appearance channel events for the minimal configuration of P2O are higher compared to DUNE, still the hierarchy sensitivity of P2O is less than DUNE because of large background events. Our results show that for a background reduction factor of 0.46 and appearance channel background systematic normalization error of $4\%$, the hierarchy sensitivity of P2O becomes equivalent of DUNE for $δ_{\rm CP} = 195^\circ$. We call this configuration of P2O as optimized P2O. Regarding the study of NSI, we find that, for $ε_{eμ}$ ($ε_{eτ}$) sensitivity of DUNE is similar (better) as compared to optimized P2O when both $ε_{eμ}$ and $ε_{eτ}$ are included in the analysis. Our results show that in presence of NSI, the change of hierarchy sensitivity with respect to standard three flavor scenario, is higher in P2O as compared to DUNE. Further, hierarchy sensitivity in presence of NSI is lower (higher) than sensitivity in the standard three flavour scenario for $δ_{\rm CP} = 270^\circ (90^\circ)$. It is important to note that hierarchy sensitivity of optimized P2O does not get significantly better than DUNE for the current favourable values of $δ_{\rm CP}$ which is $180^\circ < δ_{\rm CP} < 360^\circ$ as obtained by the global analysis in both standard three flavour and in presence of NSI.

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arXiv2021

Physics reach of the ESSnuSB experiment

ESSnuSB is a unique future proposed long-baseline experiment in Sweden to study neutrino oscillation by probing the second oscillation maximum. In this proceeding, we update the flux and efficiencies and re-calculate the sensitivity of ESSnuSB in the standard three flavour scenario. We find that it has excellent sensitivity to the Dirac CP phase $δ_{\rm CP}$, moderate sensitivity to the mass hierarchy of the neutrinos and limited sensitivity to measure the octant of the atmospheric mixing angle $θ_{23}$. We also find that it has a very good sensitivity to constrain the atmospheric mass squared difference $|Δm^2_{31}|$.

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arXiv2021

Updated sensitivity of DUNE in 3+1 scenario with far and near detectors

In this paper we present the updated physics sensitivity of DUNE in presence of a light sterile neutrino with both far and near detectors. In the previous studies, the sensitivities were obtained using the configuration of DUNE as described in the conceptual design report (CDR). In this article, we consider the configuration of DUNE as given in the technical design report (TDR) and study the capability of this experiment to constrain the sterile mixing parameters as well as its capability to measure the standard oscillation parameters in 3+1 scenario. Our results show that in 3+1 scenario, the sensitivity of DUNE to measure the mass hierarchy, octant and CP violation deteriorates if we only consider the far detector. However, a combined analysis of far and near detector improves the sensitivity.

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arXiv2021

Implications of the Dark-LMA solution for neutrino mass matrices

In this work we have re-investigated two different kinds of texture zero ansatz of the low energy neutrino mass matrix in view of the Dark-Large-Mixing-Angle (DLMA) solution of the solar neutrino problem which can arise in the presence of non-standard interactions. In particular we revisit the cases of (i) one zero mass matrices when the lowest neutrino mass is zero and (ii) one zero texture with a vanishing minor. In our study we find that for most of the cases, the texture zero conditions which are allowed for the LMA solution, are also allowed for the DLMA solution. However, we found two textures belonging to the case of one zero texture with a vanishing minor where LMA solution does not give a viable solution whereas DLMA solution does. We analyze all the possible texture zero cases belonging to these two kinds of texture zero structures in detail and present correlations between different parameters. We also present the predictions for the effective neutrino mass governing neutrino-less double beta decay for the allowed textures.

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arXiv2021

Exploring invisible neutrino decay at ESSnuSB

We explore invisible neutrino decay in which a heavy active neutrino state decays into a light sterile neutrino state and present a comparative analysis of two baseline options, $540~$km and $360~$km, for the ESSnuSB experimental setup. Our analysis shows that ESSnuSB can put a bound on the decay parameter $τ_3/m_3 = 2.64~(1.68) \times 10^{-11}~$s/eV for the baseline option of $360~(540)~$km at $3 σ$. The expected bound obtained for $360~$km is slightly better than the corresponding one of DUNE for a charged current (CC) analysis. Furthermore, we show that the capability of ESSnuSB to discover decay, and to measure the decay parameter precisely, is better for the baseline option of $540~$km than that of $360~$km. Regarding effects of decay in $δ_{\rm CP}$ measurements, we find that in general the CP violation discovery potential is better in the presence of decay. The change in CP precision is significant if one assumes decay in data but no decay in theory.

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arXiv2020

Probing Lepton Flavor Models at Future Neutrino Experiments

Non-Abelian discrete symmetries provide an interesting opportunity to address the flavor puzzle in the lepton sector. However, the number of currently viable models based on such symmetries is rather large. High-precision measurements of the leptonic mixing parameters by future neutrino experiments, including ESSnuSB, T2HK, DUNE, and JUNO, will be crucial to test such models. We show that the complementarity among these experiments offers a powerful tool for narrowing down this broad class of lepton flavor models.

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arXiv2020

Testing Lepton Flavor Models at ESSnuSB

We review and investigate lepton flavor models, stemming from discrete non-Abelian flavor symmetries, described by one or two free model parameters. First, we confront eleven one- and seven two-parameter models with current results on leptonic mixing angles from global fits to neutrino oscillation data. We find that five of the one- and five of the two-parameter models survive the confrontation test at $3σ$. Second, we investigate how these ten one- and two-parameter lepton flavor models may be discriminated at the proposed ESSnuSB experiment in Sweden. We show that the three one-parameter models that predict $\sinδ_{\rm CP}=0$ can be distinguished from those two that predict $|\sinδ_{\rm CP}|=1$ by at least $7σ$. Finally, we find that three of the five one-parameter models can be excluded by at least $5σ$ and two of the one-parameter as well as at most two of the five two-parameter models can be excluded by at least $3σ$ with ESSnuSB if the true values of the leptonic mixing parameters remain close to the present best-fit values.

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arXiv2020

Probing muonic charged current nonstandard interactions at decay-at-rest facilities in conjunction with T2HK

The muon decay-at-rest ($μ$-DAR) facility provides us with an ideal platform to probe purely muonic charged-current nonstandard neutrino interactions (NSIs). We propose to probe this class of NSI effects using antineutrinos from a $μ$-DAR source in conjunction with neutrinos from the future Tokai to Kamioka superbeam experiment with megaton Hyper Kamiokande detector (T2HK). Even though muonic NSIs are absent in neutrino production at T2HK, we show that our proposed hybrid setup comprising $μ$-DAR and T2HK helps in alleviating the parameter degeneracies that can arise in data. Analytic considerations reveal that the oscillation probability is most sensitive to the NSI parameter in the $μ$-e sector. For this parameter, we show that the $μ$-DAR setup can improve on the existing bounds down to around 0.01, especially when the data are combined with neutrino data from T2HK experiment due to the lifting of parameter degeneracies. The high precision with which $μ$-DAR can measure $δ_{\rm{CP}}$ is shown to be robust even in the presence of the considered NSIs. Finally, we show that the combination of $μ$-DAR along with T2HK can also be used to put mild constraints on the NSI phase in the vicinity of the maximal CP-violating value for the chosen benchmark value of $\varepsilon^{μe}_{μe}=0.01$.

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arXiv2020

Sensitivity to light sterile neutrinos at ESSnuSB

We present a comprehensive analysis in the 3+1 active-sterile neutrino oscillation scenario for the sensitivity of the ESSnuSB experiment in the presence of light sterile neutrinos assuming both a far (FD) and a near (ND) detector. Our analysis show that when the ND is included, the results are significantly different compared to the ones obtained with the FD only. We find that the capability of ESSnuSB to constrain the sterile mixing parameters is $\sin^22θ_{μe} \sim 10^{-4}$ for $Δm^2 = 1$ eV$^2$ if the ND is included and it becomes $\sin^22θ_{μe} \sim 10^{-2}$ without the ND. Furthermore, we show that the sensitivity can go down to $\sin^22θ_{μe} \sim 10^{-3}$ for the most conservative choice of the systematics on the ND. Comparing the sensitivity with T2HK, T2HKK, and DUNE by considering the FD only, we find that the sensitivity of ESSnuSB is smaller for most of the parameter space. Studying the CP violation sensitivity, we find that if the ND is included, it can be larger in the 3+1 scenario than in the standard one. However, if the ND is not included, the sensitivity is smaller compared to the one in the standard scenario. We also find that the CP violation sensitivity due to $δ_{13}$ is larger compared to the one induced by $δ_{24}$. The sensitivities are slightly better for the dominant neutrino running ratio of ESSnuSB.

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arXiv2020

Testing NSI suggested by the solar neutrino tension in T2HKK and DUNE

It was shown that the tension between the mass-squared differences obtained from solar neutrinos and those acquired through KamLAND experiments may be solved by the introduction of a non-standard flavor-dependent interaction (NSI) in neutrino propagation. In this study, we discuss the possibility of testing such a hypothesis using the future long-baseline neutrino experiments T2HKK and DUNE. Assuming that the NSI does not exist, we provide the excluded region within the ($ε_D$, $ε_N$) plane, where $ε_D$ and $ε_N$ are the parameters appearing in the solar neutrino analysis conducted with the NSI. We find that the best-fit value from the solar neutrino and KamLAND data (global analysis of a particular coupling to quarks) can be tested at more than 10$σ$ (3$σ$) by these two experiments for most of the parameter space.

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arXiv2020

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 $δ_{\rm CP}$. In particular, we study the effect of the neutrino mass ordering degeneracy and the leptonic mixing angle $θ_{23}$ 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 $δ_{\rm CP}$, 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 $θ_{23}$ 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 $θ_{23}$ precision in measuring $δ_{\rm CP}$.

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arXiv2019

Sensitivity study of Protvino to ORCA (P2O) experiment: Effect of antineutrino run, background and systematics

There is a proposal to send a neutrino beam from the Protvino accelerator complex located in Russia to the detector facility called `Oscillation Research with Cosmics in the Abyss' (ORCA) in the Mediterranean sea to study neutrino oscillation. This is called the P2O experiment which will have a baseline of 2588 km. In this paper, we carry out a sensitivity study to extract the best possible physics sensitivity of the P2O experiment. In particular, we study the effect of antineutrino runs, the role of background as well as the impact of controlling the systematic uncertainties vis-a-vis the statistics.

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arXiv2017

The T2HKK Experiment and Non-Standard Interaction

In this work we study the the sensitivity of the T2HKK experiment to probe non-standard interaction in neutrino propagation. As this experiment will be statistically dominated due to its large detector volume and high beam-power, it is expected that the sensitivity will be affected by systematics. This motivates us to study the effect of systematics in probing the non-standard interaction. We also compare our results with the other future proposed experiments i.e., T2HK, HK and DUNE.

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arXiv2017

Parameter degeneracy and hierarchy sensitivity of NO$ν$A in presence of sterile neutrino

The first hint of neutrino mass hierarchy is expected to come from the NO$ν$A experiment in Fermilab as the present best-fit parameter space i.e., normal hierarchy and $δ_{CP}=-90^\circ$ is the favourable parameter space for NO$ν$A where there is no degeneracy. But this situation may change if the standard three flavour framework is not complete and there is existence of new physics. In this work we consider the presence of an extra light sterile neutrino at the eV scale and study the new degeneracies which are absent in the standard three flavour framework. We also study the effect of these new degeneracies on the hierarchy measurement of NO$ν$A.

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