Browsing by Author "Saurabh Shukla"

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Analysis of Non-isotropic Lorentz Invariance Violation for NOνA Experiment in Disappearance Channel
(Springer Science and Business Media Deutschland GmbH, 2024) Saurabh Shukla; Shashank Mishra; Lakhwinder Singh; Venktesh Singh
Lorentz Invariance Violation (LIV) is a trending topic of Beyond Standard Model Physics. Lorentz symmetry is tasted and well established in the low energy realm of Physics. But there are various theories which suggest its violation for Planck scale phenomenon. As neutrinos, having tiny mass, are the particle that are breaking down the barriers of Standard Model, they may be an excellent tool for searching such Planck-suppressed signals. In order to do this study, we have opted for Standard model extension as the theoretical framewok, which contains all Lorentz violating tems in it. We study the non-isotropic LIV which causes the sidereal effect in the neutrino beamline experiment. Neutrino disappearance channel is simulated for the NOνA far detector. We find that NOνA FD is highly sensitive for the LIV and new limits of LIV coefficients are also predicted. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Determinants of survival in adult HIV patients on antiretroviral therapy in eastern Uttar Pradesh: A prospective study
(Indian Council of Medical Research, 2014) Jaya Chakravarty; Narendra K. Tiwary; Shashi Ranjan Prasad; Saurabh Shukla; Anurag Tiwari; Rabindra Nath Mishra; Shyam Sundar
Background & objectives: The National AIDS Control Organization (NACO) of India has been providing free ARV (antiretroviral) drugs since 2004. By 2012, 486,173 patients had received treatment through the antiretroviral therapy (ART) centres. The objective of this observational study was to assess the factors determining survival of patients on ART under routine programme conditions in an ART centre in north India five years after its inception.; Methods: Treatment naive HIV positive patients who were enrolled in the ART centre between May 2009 and May 2010 and started on ART as per the Revised NACO guidelines 2009, were included in the study and outcome was assessed after two years of follow up.; Results: A total of 1689 patients were included in the analysis, of whom 272 (16.10%) expired, 205 (12.13%) were lost to follow up (LFU), 526 (31.14%) were transferred out to other facilities and 686 (40.63%) were alive at the end of two years. Majority (92%) of the deaths occurred in the first six months of therapy. Age >30 yr, male gender, poor functional status, haemoglobin level <11 g/dl, body weight <45 kg and CD4 count <100/ul at baseline had significantly higher relative hazard of death. Most LFU also occurred in the first six months and these patients had significantly low CD4 count, weight, haemoglobin level and higher number of patients in Stages III and IV as compared to those who survived.; Interpretation & conclusions: The study findings revealed poor survival in the first six months of therapy especially in those with severe immunosuppression. This emphasizes the need for early enrolment into the programme. The high LFU occurring early after initiation of therapy suggests the urgent need to build an efficient patient retrieval system in the programme. © 2014, Indian Council of Medical Research. All rights reserved.
Investigating Lorentz invariance violation effects on CP violation and mass hierarchy sensitivity at DUNE
(American Physical Society, 2024) Saurabh Shukla; Shashank Mishra; Lakhwinder Singh; Venktesh Singh
One of the current goals of neutrino experiments is to precisely determine standard unknown oscillation parameters such as the leptonic CP phase and mass hierarchy. Lorentz invariance violation represents a potential physics factor that could influence the experiment's ability to achieve these precise determinations. This study investigates the influence of Lorentz invariance violation on oscillation dynamics, particularly through nonisotropic CPT-violating (aeμX, aeτX, aμτX) and CPT-conserving (ceμXY, ceτXY, cμτXY) parameters within the Deep Underground Neutrino Experiment. We analyze the impact of these parameters on the mass hierarchy (MH) and Dirac CP phase sensitivity measurements. Our findings indicate that while MH sensitivity remains relatively unaffected, only the presence of cμτXY significantly deteriorates MH sensitivity, albeit remaining above the 5σ threshold. Additionally, we observe a substantial compromise in CP sensitivity due to the ceμXY and ceτXY parameters. © 2024 authors. Published by the American Physical Society.
Joint neutrino oscillation analysis from the T2K and NOvA experiments
(Nature Research, 2025) Robert Miles Zwaska; Jaroslav Zalesak; S. Zadorozhnyy; Katsuya Yonehara; Alejandro Yankelevich; A. Yahaya; Barbara Yaeggy; Yiwen Xiao; Wanwei Wu; Shuai Wu; Jeremy A. Wolcott; Don Athula A. Wickremasinghe; D. W. Whittington; Matthew J. Wetstein; C. Weber; Thomas K. Warburton; Michael Wallbank; Abigail Victoria Waldron; K. J. Vockerodt; Z. Vallari; P. L. Vahle; Jon Urheim; J. Trokan-Tenorio; D. Tran; Yagmur Torun; M. Titus; Emrah Tiras; Jennifer A. Thomas; Tarak Thakore; P. Tas; N. Talukdar; Artur A. Sztuc; C. Sweeney; S. Swain; Andrew Sutton; Louise Suter; Matthew Strait; Karel Soustružník; Alexandre B. Sousa; Nickolas Solomey; Pavel V. Snopok; Jan Smolík; A. Smith; Dinesh Kumar Singha; Simranjit Singh Chhibra; Venktesh Singh; Prabhjot Singh; Ishwar Singh; Saurabh Shukla; W. Shorrock; Alexander K. Shmakov; Shivam; Andrey S. Sheshukov; P. Sharma; Peter Shanahan; S. Sánchez Falero; Mayly Calderón De La Barca Sánchez; O. B. Samoylov; P. K. Roy; Edgar E. Robles; Brian J. Rebel; Bryan J. Ramson; Miriama Rajaoalisoa; V. Raj; Aleena Rafique; L. R. Prais; J. C.C. Porter; Robert K. Plunkett; Roberto Petti; G. Pawloski; Ryan B. Patterson; Lipsarani Panda; Jonathan M. Paley; A. Pal; Mustafa Ozkaynak; T. Olson; Alexander G. Olshevskiy; H. Oh; A. Norrick; Andrew J. Norman; Evan Niner; Ryan J. Nichol; Jeffery K. Nelson; S. Nelleri; Donna L. Naples; D. Myers; Kevin Mulder; Mathew Muether; Leon Mualem; Wei Mu; A. D. Morozova; Adam Moren; Mohanta K. Rukmani; Sanjib Ratan Mishra; W. H. Miller; Ting Miao; Holger Meyer; M. D. Messier; Bhumika Mehta; Viktor A. Matveev
The landmark discovery that neutrinos have mass and can change type (or flavour) as they propagate—a process called neutrino oscillation1, 2, 3, 4, 5–6—has opened up a rich array of theoretical and experimental questions being actively pursued today. Neutrino oscillation remains the most powerful experimental tool for addressing many of these questions, including whether neutrinos violate charge-parity (CP) symmetry, which has possible connections to the unexplained preponderance of matter over antimatter in the Universe7, 8, 9, 10–11. Oscillation measurements also probe the mass-squared differences between the different neutrino mass states (Δm2), whether there are two light states and a heavier one (normal ordering) or vice versa (inverted ordering), and the structure of neutrino mass and flavour mixing12. Here we carry out the first joint analysis of datasets from NOvA13 and T2K14, the two currently operating long-baseline neutrino oscillation experiments (hundreds of kilometres of neutrino travel distance), taking advantage of our complementary experimental designs and setting new constraints on several neutrino sector parameters. This analysis provides new precision on the Δm322 mass difference, finding 2.43−0.03+0.04×10−3eV2 in the normal ordering and −2.48−0.04+0.03×10−3eV2 in the inverted ordering, as well as a 3σ interval on δCP of [−1.38π, 0.30π] in the normal ordering and [−0.92π, −0.04π] in the inverted ordering. The data show no strong preference for either mass ordering, but notably, if inverted ordering were assumed true within the three-flavour mixing model, then our results would provide evidence of CP symmetry violation in the lepton sector. © The Author(s) 2025.
Search for Lorentz violations through the sidereal effect at the NOν A experiment
(American Physical Society, 2024) Shashank Mishra; Saurabh Shukla; Lakhwinder Singh; Venktesh Singh
Long-baseline neutrino oscillation experiments offer a unique laboratory to test the fundamental Lorentz symmetry, which is at the heart of both the standard model of particle and general relativity theory. The sidereal modulation in neutrino events will act as the smoking-gun experimental signature of Lorentz and CPT violation. In this study, we investigate the impact of the sidereal effect on standard neutrino oscillation measurements within the context of the NuMI Off-Axis νe Appearance Experiment (NOνA) experiment. Additionally, we assess the sensitivity of the NOνA experiment to detect Lorentz-violating interactions, taking into account the sidereal effect. Furthermore, we highlight the potential of the NOνA experiment to set new constraints on anisotropic Lorentz-violating parameters. © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
The Impact of Sidereal Variation on Time-Independent Probability Analysis in Neutrino Long-Baseline Experiments
(Springer Science and Business Media Deutschland GmbH, 2024) Shashank Mishra; Saurabh Shukla; Lakhwinder Singh; Venktesh Singh
Lorentz invariance is a well-known fundamental symmetry, serving as the pillar of widely accepted theories such as quantum field theory and Einstein theory of relativity, and has deep connections with the charge, parity, and time-reversal symmetry. The search for Lorentz invariance violation (LIV) is getting more attention in recent years due to many theories of beyond standard model (Stochastic space-time foam, quantum loop gravity, string theory, etc.) predicting LIV in high-energy physics. We adopt the non-isotropic model to study the LIV parameters. We compare the impact of LIV in different long-baseline neutrino experiments and shows how they are sensitivity depends on their position and orientation. We have also investigated the effect of the non-isotropic LIV parameter on disappearance channels in time-independent analysis. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.