974 results on '"Nir, Yosef"'
Search Results
2. $C{\hspace{-1.69998pt}}P$ violation in $B$ decays
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Nir, Yosef and Vagnoni, Vincenzo
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Meson ,Decay ,LHC ,Large Hadron Collider ,CP symmetry violation ,Physics ,QC1-999 - Abstract
The experimental study of CP violation in $B$ decays has led to significant progress in our understanding of nature: (i) It demonstrated that the Kobayashi-Maskawa mechanism is the dominant source of CP violation in meson decays. (ii) It improved significantly the precision in the determination of the parameters of the Cabibbo–Kobayashi–Maskawa quark-mixing matrix. (iii) It proved that new physics that has order-one flavour-changing couplings to the $b$ quark should be characterised by a mass scale higher than $\mathcal{O}(10^3~\mathrm{TeV})$. Further progress is expected from the Belle II and LHC experiments during the next decade and beyond. Present status and perspectives are here discussed.
- Published
- 2020
- Full Text
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3. Lessons from ATLAS and CMS measurements of Higgs boson decays to second generation fermions
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Nir, Yosef and Udhayashankar, Purvaash Panduranghan
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
There is now experimental evidence for Higgs boson decay into a pair of muons, and significant constraints on the Higgs boson decay into a charm quark-antiquark pair. The data on Higgs boson decays into second generation fermions probes various extensions of the Standard Model. We analyze the implications for the Standard Model effective field theory (SMEFT), without and with minimal flavor violation (MFV), for two Higgs doublet models (2HDM) with natural flavor conservation (NFC), for models with vector-like fermions, and for specific models that predict significant modifications of the Yukawa couplings to the light generations., Comment: 19 pages, 3 figures
- Published
- 2024
4. The flavor of a light charged Higgs
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Bernal, Nicolás, Losada, Marta, Nir, Yosef, and Shpilman, Yogev
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High Energy Physics - Phenomenology - Abstract
The ATLAS Collaboration has recently reported a search for light-charged Higgs in $t\to H^+ b$ decay, with $H^+\to c\bar b$. An excess with a local significance of approximately $3\sigma$ is found at $m_{H^+}\approx130$ GeV, with a best-fit value of ${\rm BR}(t\to H^+b)\times {\rm BR}(H^+\to c\bar b)=(1.6\pm0.6)\times10^{-3}$. We study the implications of such a hypothetical signal in multi-Higgs doublet models. We take into account constraints from searches for other charged Higgs decays and from flavor-changing neutral current processes. Two Higgs doublet models with flavor structure dictated by natural flavor conservation (NFC), minimal flavor violation (MFV), or the Froggatt-Nielsen (FN) mechanism cannot account for such excess. A three-Higgs doublet model with NFC can account for the signal. The Yukawa couplings of the neutral pseudoscalar $A$ in the down sector, $\hat Y_A^D$, should be larger by a factor of $4-6$ compared to the corresponding Yukawa couplings of the Higgs $h$, $\hat Y_h^D$. We further present two minimal scenarios, one in which a single Yukawa coupling in the down sector, $(\hat Y_A^D)_{bb}$, gives the only significant contribution, and one in which two Yukawa couplings in the up sector, $(\hat Y_A^U)_{tt}$ and $(\hat Y_A^U)_{tc}$, give the only significant contributions, and we discuss possible tests of these scenarios., Comment: 19 pages, 4 figures
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- 2023
5. Comprehensive network modeling approaches unravel dynamic enhancer-promoter interactions across neural differentiation
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William DeGroat, Fumitaka Inoue, Tal Ashuach, Nir Yosef, Nadav Ahituv, and Anat Kreimer
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Functional genomics ,Gene regulation ,Neural development ,Computational genomics ,Biology (General) ,QH301-705.5 ,Genetics ,QH426-470 - Abstract
Abstract Background Increasing evidence suggests that a substantial proportion of disease-associated mutations occur in enhancers, regions of non-coding DNA essential to gene regulation. Understanding the structures and mechanisms of the regulatory programs this variation affects can shed light on the apparatuses of human diseases. Results We collect epigenetic and gene expression datasets from seven early time points during neural differentiation. Focusing on this model system, we construct networks of enhancer-promoter interactions, each at an individual stage of neural induction. These networks serve as the base for a rich series of analyses, through which we demonstrate their temporal dynamics and enrichment for various disease-associated variants. We apply the Girvan-Newman clustering algorithm to these networks to reveal biologically relevant substructures of regulation. Additionally, we demonstrate methods to validate predicted enhancer-promoter interactions using transcription factor overexpression and massively parallel reporter assays. Conclusions Our findings suggest a generalizable framework for exploring gene regulatory programs and their dynamics across developmental processes; this includes a comprehensive approach to studying the effects of disease-associated variation on transcriptional networks. The techniques applied to our networks have been published alongside our findings as a computational tool, E-P-INAnalyzer. Our procedure can be utilized across different cellular contexts and disorders.
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- 2024
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6. NF-κB inhibitor alpha controls SARS-CoV-2 infection in ACE2-overexpressing human airway organoids
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Camille R. Simoneau, Pei-Yi Chen, Galen K. Xing, Jennifer M. Hayashi, Irene P. Chen, Mir M. Khalid, Nathan L. Meyers, Taha Y. Taha, Kristoffer E. Leon, Rahul K. Suryawanshi, Maria McCavitt-Malvido, Tal Ashuach, Krystal A. Fontaine, Lauren Rodriguez, Bastian Joehnk, Keith Walcott, Sreelakshmi Vasudevan, Xiaohui Fang, Mazharul Maishan, Shawn Schultz, Jeroen P. Roose, Michael A. Matthay, Anita Sil, Mehrdad Arjomandi, Nir Yosef, and Melanie Ott
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Medicine ,Science - Abstract
Abstract As SARS-CoV-2 continues to spread worldwide, tractable primary airway cell models that recapitulate the cell-intrinsic response to arising viral variants are needed. Here we describe an adult stem cell-derived human airway organoid model overexpressing the ACE2 receptor (ACE2-OE) that supports robust viral replication while maintaining 3D architecture and cellular diversity of the airway epithelium. ACE2-OE organoids were infected with SARS-CoV-2 variants and subjected to single-cell RNA-sequencing. Interferon-lambda was upregulated in cells with low-level infection while the NF-kB inhibitor alpha gene (encoding IkBa) was consistently upregulated in infected cells, and its expression positively correlated with infection levels. Confocal microscopy showed more IkBa expression in infected than bystander cells, but found concurrent nuclear translocation of NF-kB that IkBa usually prevents. Overexpressing a nondegradable IkBa mutant reduced NF-kB translocation and increased viral infection. These data demonstrate the functionality of ACE2-OE organoids in SARS-CoV-2 research and underscore that the strength of the NF-kB feedback loop in infected cells controls viral replication.
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- 2024
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7. Time Dependent CP-even and CP-odd Signatures of Scalar Ultra-light Dark Matter in Neutrino Oscillations
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Losada, Marta, Nir, Yosef, Perez, Gilad, Savoray, Inbar, and Shpilman, Yogev
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
Scalar ultra-light dark matter (ULDM) interacting with neutrinos can induce, under certain conditions, time-dependent modifications to neutrino oscillation probabilities. The limit in which the ULDM perturbation can be treated as constant throughout the neutrino propagation time has been addressed by several previous works. We complement these by systematically analyzing the opposite limit -- accounting for the temporal-variations of the ULDM potential by solving time-dependent Schr\"odinger equations. In particular, we study a novel two-generations-like CP violating (CPV) signature unique to rapidly oscillating ULDM. We derive the leading order, time-dependent, corrections to the oscillation probabilities, both for CP conserving (CPC) and CPV couplings, and explain how they can be measured in current and future experiments., Comment: 23 pages, 1 figure
- Published
- 2023
8. The branching fraction of $B_s\to K^0\bar K^0$: Three puzzles
- Author
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Amhis, Yasmine, Grossman, Yuval, and Nir, Yosef
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High Energy Physics - Phenomenology - Abstract
The branching fraction of the $B_s\to K^0\bar K^0$ decay has been recently measured by the LHCb and Belle experiments. We study the consistency of the measured value with three relations to other decay rates and CP asymmetries which follow from the Standard Model, and from the approximate flavor $SU(3)$ symmetry of the strong interactions. We find that each of these relations is violated at a level of above $3\sigma$. We argue that various subleading effects -- rescattering, electroweak penguins and $SU(3)$ breaking -- if larger than theoretically expected, can account for some of these puzzles, but not for all of them simultaneously., Comment: 16 pages, no figures; v2: minor changes, two references added
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- 2022
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9. Parametric resonance in neutrino oscillations induced by ultra-light dark matter and implications for KamLAND and JUNO
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Losada, Marta, Nir, Yosef, Perez, Gilad, Savoray, Inbar, and Shpilman, Yogev
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
If ultra-light dark matter (ULDM) exists and couples to neutrinos, the neutrino oscillation probability might be significantly altered by a parametric resonance. This resonance can occur if the typical frequency of neutrino flavor-oscillations $\Delta m^2/(2E)$, where $\Delta m^2$ is the mass-squared difference of the neutrinos and $E$ is the neutrino energy, matches the oscillation frequency of the ULDM field, determined by its mass, $m_\phi$. The resonance could lead to observable effects even if the ULDM coupling is very small, and even if its typical oscillation period, given by $\tau_\phi=2\pi/m_\phi$, is much shorter than the experimental temporal resolution. Defining a small parameter $\epsilon_\phi$ to be the ratio between the contribution of the ULDM field to the neutrino mass and the vacuum value of the neutrino mass, the impact of the resonance is particularly significant if $\epsilon_\phi m_\phi L\gtrsim 4$, where $L$ is the distance between the neutrino source and the detector. Such parametric resonance can improve the fit to the KamLAND experiment measurements by about $3.5\,\sigma$ compared to standard oscillations. This scenario will be tested by the JUNO experiment., Comment: 12 pages, 3 figures
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- 2022
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10. $b\to c\tau\bar\nu_{e,\mu}$ contributions to $R(D^{(*)})$
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Bressler, Shikma, Halevy, Federico De Vito, and Nir, Yosef
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
The $R(D^{(*)})$ puzzle stands for a $\sim3\sigma$ violation of lepton flavor universality between the decay rates of $B\to D^{(*)}\tau\nu$ and $B\to D^{(*)}\ell\nu$, where $\ell=e,\mu$. If it is accounted for by new physics, there is no reason in general that the relevant neutrinos are, respectively, $\nu_\tau$ and $\nu_\ell$. We study whether the $\tau$ related rate could be enhanced by significant contributions to $B\to D^{(*)}\tau\nu_\ell$ from a class of operators in the Standard Model Effective Field Theory (SMEFT). We find the upper bounds from forbidden or rare meson decays imply that the contributions from the lepton flavor violating processes account for no more than about $4\%$ of the required shift. Yet, no fine-tuned flavor alignment is required for the new physics. Searching for the related high-$p_T$ process $pp\to\tau^\pm\mu^\mp$ can at present put a lower bound on the scale of the lepton flavor violating new physics that is a factor of $2.2$ weaker than the bound from meson decays. An exception to our conclusion arises from a specific combination of scalar and tensor SMEFT operators., Comment: 10 pages; v2: References added; v3: Added discussion of scalar and tensor operators and of flavor constraints from charmed mesons
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- 2022
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11. Lessons from the LHCb measurement of CP violation in $B_s\to K^+K^-$
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Nir, Yosef, Savoray, Inbar, and Viernik, Yehonatan
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
The LHCb experiment measured the time-dependent CP asymmetries $C_{KK}$ and $S_{KK}$ in $B_s\to K^+K^-$ decay. Combining with the corresponding CP asymmetries $C_{\pi\pi}$ and $S_{\pi\pi}$ in $B\to \pi^+\pi^-$ decay, we find that the size of $U$-spin breaking in this system is of order $20\%$. Moreover, the data suggest that these effects are dominated by factorizable contributions. We further study the constraints on new physics contributions to $b\to u\bar uq$ ($q=s,d$). New physics that is minimally flavor violating (MFV) cannot be distinguished from the Standard Model (SM) in these decays. However, new physics that is not MFV can mimic large $U$-spin breaking. Requiring that the $U$-spin breaking parameters remain below the size implied by the data leads to a lower bound of $5-10$ TeV on the scale of generic new physics. If the new physics is subject to the selection rules that follow from the Froggatt-Nielsen (FN) mechanism or from General Minimal Flavor Violation (GMFV), the bound is relaxed to 2 TeV., Comment: 22 pages, 1 figure
- Published
- 2022
12. Probing scalar dark matter oscillations with neutrino oscillations
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Losada, Marta, Nir, Yosef, Perez, Gilad, and Shpilman, Yogev
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
If ultra-light dark matter (ULDM) exists and couples to neutrinos, it can be discovered via time-periodic variations in the neutrino mass and mixing parameters. We analyze the current bounds on such a scenario and establish the sensitivity expected for both time-averaged and time-resolved modulations in future neutrino oscillation experiments. We place a special emphasis in our analysis on time modulations of the CP violating mixing phase. We illustrate with a toy model the case where the leading modulation effect can be CP violating while the effect on CP conserving parameters is suppressed. We show a unique imprint that a time averaged CP violating modulation of ULDM can leave in neutrino oscillations, while direct CP asymmetries vanish., Comment: 25 pages, 8 figures
- Published
- 2021
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13. The three jewels in the crown of the LHC
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Nir, Yosef
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High Energy Physics - Phenomenology - Abstract
The ATLAS and CMS experiments have made three major discoveries: The discovery of an elementary spin-zero particle, the discovery of the mechanism that makes the weak interactions short-range, and the discovery of the mechanism that gives the third generation fermions their masses. I explain how this progress in our understanding of the basic laws of Nature was achieved., Comment: 5 pages
- Published
- 2020
14. The academic career in physics as a 'deal': Choosing physics within a gendered power structure and excellence as an extra hurdle for women
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Eran-Jona, Meytal and Nir, Yosef
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Physics - Physics Education - Abstract
The absence of women among academic staff in physics is in the focus of our research. To explore the causes of this gender imbalance, we conducted a nationwide representative survey among Ph.D. students and interviews with Ph.D. students and postdoctoral fellows. Studying both context factors and agency, we reveal the multiple and hidden ways in which gender operates as a power structure, putting up barriers to women's academic careers. This latent power structure influences women's decision-making and experiences in several ways. In the academic field, it produces unequal competition in a male dominated playground. In the social sphere, choosing a demanding academic career is seen as disrupting gender order. Within the family, women carry a greater burden of family work and give precedence to their partner's career and preferences. Within this social structure, women who decide to follow an academic career feel that they must excel. The demand for excellence acts as an invisible barrier within the gender power structure that prevents talented women from pursuing an academic career in physics., Comment: 13 pages
- Published
- 2020
- Full Text
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15. Analytic Techniques for Solving the Transport Equations in Electroweak Baryogenesis
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Fuchs, Elina, Losada, Marta, Nir, Yosef, and Viernik, Yehonatan
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High Energy Physics - Phenomenology ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We develop an efficient method for solving transport equations, particularly in the context of electroweak baryogenesis. It provides fully-analytical results under mild approximations and can also test semi-analytical results, which are applicable in more general cases. Key elements of our method include the reduction of the second-order differential equations to first order, representing the set of coupled equations as a block matrix of the particle densities and their derivatives, identification of zero modes, and block decomposition of the matrix. We apply our method to calculate the baryon asymmetry of the Universe (BAU) in a Standard Model effective field theory framework of complex Yukawa couplings to determine the sensitivity of the resulting BAU to modifications of various model parameters and rates, and to estimate the effect of the commonly-used thin-wall approximation., Comment: 23 pages + 3 appendices, 9 figures, 4 tables
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- 2020
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16. Ph.D. in physics as a hurdle race, and the 'glass hurdles' for women
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Eran-Jona, Meytal and Nir, Yosef
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Physics - Physics Education ,Physics - Physics and Society - Abstract
On their way to an academic career in physics, Ph.D. students have to overcome difficulties at many levels. Beyond the intellectual challenge, there are also psychological, social and economic barriers. We studied the difficulties experienced by physics Ph.D. students in the Israeli universities, with special attention to gender-related issues. Among the hurdles that are much more significant for women than for men -- that we call ``the glass hurdles" -- we find gender-related discrimination, sexual harassment, physiological and psychological health issues, and challenges related to pregnancy and parenthood. We make recommendations for ways to confront and remove these barriers in order to provide female physicists with an equal opportunity to succeed., Comment: 8 pages, 5 figures
- Published
- 2020
17. $CP$ violation from $\tau$, $t$ and $b$ dimension-6 Yukawa couplings -- interplay of baryogenesis, EDM and Higgs physics
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Fuchs, Elina, Losada, Marta, Nir, Yosef, and Viernik, Yehonatan
- Subjects
High Energy Physics - Phenomenology ,Astrophysics - Cosmology and Nongalactic Astrophysics ,High Energy Physics - Experiment - Abstract
We explore the implications of the Standard Model effective field theory (SMEFT) with dimension-six terms involving the Higgs boson and third-generation fermion fields on the rate of Higgs boson production and decay into fermions, on the electric dipole moments (EDMs) of the electron, and on the baryon asymmetry of the Universe. We study the consequences of allowing these additional terms for each flavor separately and for combinations of two flavors. We find that a complex $\tau$ Yukawa coupling can account for the observed baryon asymmetry $Y_B^{\rm obs}$ within current LHC and EDM bounds. A complex $b$ ($t$) Yukawa coupling can account for $4\%$ ($2\%$) of $Y_B^{\rm obs}$, whereas a combination of the two can reach $12\%$. Combining $\tau$ with either $t$ or $b$ enlarges the viable parameter space owing to cancellations in the EDM and in either Higgs production times decay or the total Higgs width, respectively. Interestingly, in such a scenario there exists a region in parameter space where the SMEFT contributions to the electron EDM cancel and collider signal strengths are precisely SM-like, while producing sufficient baryon asymmetry. Measuring $CP$ violation in Higgs decays to $\tau$ leptons is the smoking gun for this scenario., Comment: 20 pages + appendix, 5 figures, 3 tables
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- 2020
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18. Hepatitis C virus infects and perturbs liver stem cells
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Nathan L. Meyers, Tal Ashuach, Danielle E. Lyons, Mir M. Khalid, Camille R. Simoneau, Ann L. Erickson, Mehdi Bouhaddou, Thong T. Nguyen, G. Renuka Kumar, Taha Y. Taha, Vaishaali Natarajan, Jody L. Baron, Norma Neff, Fabio Zanini, Tokameh Mahmoudi, Stephen R. Quake, Nevan J. Krogan, Stewart Cooper, Todd C. McDevitt, Nir Yosef, and Melanie Ott
- Subjects
hepatitis c virus ,organoid ,liver disease ,stem cell ,single-cell RNA sequencing ,chronic infection ,Microbiology ,QR1-502 - Abstract
ABSTRACTHepatitis C virus (HCV) is the leading cause of death from liver disease. How HCV infection causes lasting liver damage and increases cancer risk remains unclear. Here, we identify bipotent liver stem cells as novel targets for HCV infection, and their erroneous differentiation as the potential cause of impaired liver regeneration and cancer development. We show 3D organoids generated from liver stem cells from actively HCV-infected individuals carry replicating virus and maintain low-grade infection over months. Organoids can be infected with a primary HCV isolate. Virus-inclusive single-cell RNA sequencing uncovered transcriptional reprogramming in HCV+ cells supporting hepatocytic differentiation, cancer stem cell development, and viral replication while stem cell proliferation and interferon signaling are disrupted. Our data add a new pathogenesis mechanism—infection of liver stem cells—to the biology of HCV infection that may explain progressive liver damage and enhanced cancer risk through an altered stem cell state.IMPORTANCEThe hepatitis C virus (HCV) causes liver disease, affecting millions. Even though we have effective antivirals that cure HCV, they cannot stop terminal liver disease. We used an adult stem cell-derived liver organoid system to understand how HCV infection leads to the progression of terminal liver disease. Here, we show that HCV maintains low-grade infections in liver organoids for the first time. HCV infection in liver organoids leads to transcriptional reprogramming causing cancer cell development and altered immune response. Our finding shows how HCV infection in liver organoids mimics HCV infection and patient pathogenesis. These results reveal that HCV infection in liver organoids contributes to liver disease progression.
- Published
- 2023
- Full Text
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19. Implications of the upper bound on $\boldsymbol{h\to\mu^+\mu^-}$ on the baryon asymmetry of the Universe
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Fuchs, Elina, Losada, Marta, Nir, Yosef, and Viernik, Yehonatan
- Subjects
High Energy Physics - Phenomenology - Abstract
The upper bounds from the ATLAS and CMS experiments on the decay rate of the Higgs boson to two muons provide the strongest constraint on an imaginary part of the muon Yukawa coupling. This bound is more than an order of magnitude stronger than bounds from $\mathcal{CP}$-violating observables, specifically the electric dipole moment of the electron. It excludes a scenario $-$ which had been viable prior to these measurements $-$ that a complex muon Yukawa coupling is the dominant source of the baryon asymmetry. Even with this bound, the muon source can still contribute ${\cal O}(16\%)$ of the asymmetry., Comment: 5 pages, 1 figure
- Published
- 2019
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20. Implications of the LHCb discovery of CP violation in charm decays
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Dery, Avital and Nir, Yosef
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High Energy Physics - Phenomenology - Abstract
The recent measurement of $\Delta A_{CP}$ by the LHCb collaboration requires an ${\cal O}(10)$ enhancement coming from hadronic physics in order to be explained within the SM. We examine to what extent can NP models explain $\Delta A_{CP}$ without such enhancements. We discuss the implications in terms of a low energy effective theory as well as in the context of several explicit NP models.
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- 2019
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21. The Higgs program and open questions in particle physics and cosmology
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Heinemann, Beate and Nir, Yosef
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
The Higgs program is relevant to many of the open fundamental questions in particle physics and in cosmology. Thus, when discussing future collider experiments, one way of comparing them is by assessing their potential contributions to progress on these questions. We discuss in detail the capabilities of the various proposed experiments in searching for singlet scalars, which are relevant to several of the open questions, and in measuring Higgs decays to fermion pairs, which are relevant to the flavor puzzles. On other interesting questions, we list the most relevant observables within the Higgs program., Comment: 17 pages, 1 figure
- Published
- 2019
- Full Text
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22. Parametric resonance in neutrino oscillations induced by ultra-light dark matter and implications for KamLAND and JUNO
- Author
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Losada, Marta, Nir, Yosef, Perez, Gilad, Savoray, Inbar, and Shpilman, Yogev
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- 2023
- Full Text
- View/download PDF
23. Neutrinoless double-beta decay with massive scalar emission
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Blum, Kfir, Nir, Yosef, and Shavit, Michal
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High Energy Physics - Phenomenology - Abstract
Searches for neutrino-less double-beta decay ($0\nu2\beta$) place an important constraint on models where light fields beyond the Standard Model participate in the neutrino mass mechanism. While $0\nu2\beta$ experimental collaborations often consider various massless majoron models, including various forms of majoron couplings and multi-majoron final-state processes, none of these searches considered the scenario where the "majoron" $\phi$ is not massless, $m_\phi\sim$~MeV, of the same order as the $Q$-value of the $0\nu2\beta$ reaction. We consider this parameter region and estimate $0\nu2\beta\phi$ constraints for $m_\phi$ of order MeV. The constraints are affected not only by kinematical phase space suppression but also by a change in the signal to background ratio characterizing the search. As a result, $0\nu2\beta\phi$ constraints for $m_\phi>0$ diminish significantly below the reaction threshold. This has phenomenological implications, which we illustrate focusing on high-energy neutrino telescopes. Our results motivate a dedicated analysis by $0\nu2\beta$ collaborations, analogous to the dedicated analyses targeting massless majoron models., Comment: 9 pages, 6 figures. v2: added App.A w/ phase space integrals, a few added comments, match journal version
- Published
- 2018
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24. Large Higgs-electron Yukawa coupling in 2HDM
- Author
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Dery, Avital, Frugiuele, Claudia, and Nir, Yosef
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High Energy Physics - Phenomenology - Abstract
The present upper bound on $\kappa_e$, the ratio between the electron Yukawa coupling and its Standard Model value, is of ${\cal O}(600)$. We ask what would be the implications in case that $\kappa_e$ is close to this upper bound. The simplest extension that allows for such enhancement is that of two Higgs doublet models (2HDM) without natural flavor conservation. In this framework, we find the following consequences: (i) Under certain conditions, measuring $\kappa_e$ and $\kappa_V$ would be enough to predict values of Yukawa couplings for other fermions and for the $H$ and $A$ scalars. (ii) In the case that the scalar potential has a softly broken $Z_2$ symmetry, the second Higgs doublet must be light, but if there is hard breaking of the symmetry, the second Higgs doublet can be much heavier than the electroweak scale and still allow the electron Yukawa coupling to be very different from its SM value. (iii) CP must not be violated at a level higher than ${\cal O}(0.01/\kappa_e)$ in both the scalar potential and the Yukawa sector. (iv) LHC searches for $e^+e^-$ resonances constrain this scenario in a significant way. Finally, we study the implications for models where one of the scalar doublets couples only to the first generation, or only to the third generation., Comment: 14 pages, 2 figures
- Published
- 2017
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25. Choosing Physics within a Gendered Power Structure: The Academic Career in Physics as a 'Deal'
- Author
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Eran-Jona, Meytal and Nir, Yosef
- Abstract
This research focuses on the absence of women among academic staff in physics. To explore the causes of this gender imbalance, we focus on the decision-making junction between obtaining a Ph.D. diploma and pursuing a postdoctoral position. We use the mixed-methods paradigm, combining a nationwide representative survey of Ph.D. students in Israel (n = 267 respondents out of 404 questioned) and interviews with Ph.D. students and postdoctoral fellows (n = 38). The theoretical novelty that we propose is to view such career decision making as a "deal" that involves contextual, organizational, and individual variables and their intersection. Young women are examining the components of this deal: what it offers them and what prices they will have to pay, but their decision is made within a gendered power structure. Studying both context factors and agency, we reveal the multiple hidden ways in which gender operates as a power structure, putting up barriers to women's academic careers. This latent power structure influences women's decision making and experiences in several ways. In the academic field, it produces unequal competition in a male-dominated playground. In the social sphere, choosing a demanding academic career is seen as disrupting gender order. Within the family, women carry a greater burden of family work and give precedence to their husband's career and preferences. Within this social structure, women who decide to follow an academic career feel that they must excel, and this demand for "excellence" acts as a hidden mechanism within the gendered power structure that may prevent talented women from pursuing an academic career in physics.
- Published
- 2021
- Full Text
- View/download PDF
26. The branching fraction of Bs0→K0K¯0: three puzzles
- Author
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Amhis, Yasmine, Grossman, Yuval, and Nir, Yosef
- Published
- 2023
- Full Text
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27. Massively parallel reporter perturbation assays uncover temporal regulatory architecture during neural differentiation
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Anat Kreimer, Tal Ashuach, Fumitaka Inoue, Alex Khodaverdian, Chengyu Deng, Nir Yosef, and Nadav Ahituv
- Subjects
Science - Abstract
How gene regulatory elements regulate gene expression during cellular differentiation remains largely unknown. Here the authors use perturbation-based massively parallel reporter assays at early time points of neural differentiation to systematically characterize how regulatory elements and motifs within them guide different transcriptional patterns.
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- 2022
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28. Testing Minimal Flavor Violation in Leptoquark Models of the $R_{K^{(*)}}$ Anomaly
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Aloni, Daniel, Dery, Avital, Frugiuele, Claudia, and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
The $R_{K^{(*)}}$ anomaly can be explained by tree level exchange of leptoquarks. We study the consequences of subjecting these models to the principle of minimal flavor violation (MFV). We consider MFV in the linear regime, and take the charged lepton Yukawa matrix to be the only spurion that violates lepton flavor universality. We find that a combination of constraints from a variety of processes -- $b\to s\mu\mu$, $b\to s\tau\tau$, $b\to s\nu\nu$, $b\bar b\to\tau\tau$ and $b\to c\tau\nu$ -- excludes MFV in these models., Comment: Version published in JHEP, 15 pages, 1 figure
- Published
- 2017
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29. $\Upsilon$ and $\psi$ leptonic decays as probes of solutions to the $R_D^{(*)}$ puzzle
- Author
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Aloni, Daniel, Efrati, Aielet, Grossman, Yuval, and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
Experimental measurements of the ratios $R(D^{(*)})\equiv\frac{\Gamma(B\to D^{(*)}\tau\nu)}{\Gamma(B\to D^{(*)}\ell\nu)}$ ($\ell=e,\mu$) show a $3.9\sigma$ deviation from the Standard Model prediction. In the absence of light right-handed neutrinos, a new physics contribution to $b\to c\tau\nu$ decays necessarily modifies also $b\bar b\to\tau^+\tau^-$ and/or $c\bar c\to\tau^+\tau^-$ transitions. These contributions lead to violation of lepton flavor universality in, respectively, $\Upsilon$ and $\psi$ leptonic decays. We analyze the constraints resulting from measurements of the leptonic vector-meson decays on solutions to the $R(D^{(*)})$ puzzle. Available data from BaBar and Belle can already disfavor some of the new physics explanations of this anomaly. Further discrimination can be made by measuring $\Upsilon(1S,2S,3S)\to\tau\tau$ in the upcoming Belle II experiment., Comment: Version published in JHEP, 17 pages, 7 figures
- Published
- 2017
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30. FN-2HDM: Two Higgs Doublet Models with Froggatt-Nielsen Symmetry
- Author
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Dery, Avital and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
We embed Two Higgs Doublet Models (2HDMs) in the Froggatt Nielsen (FN) framework. We find that the approximate FN symmetry predicts i) approximate Natural Flavor Conservation (NFC) of Types II or IV in the Yukawa sector, and ii) approximate Peccei-Quinn (PQ) symmetry in the scalar sector. We discuss the phenomenological consequences of these features.
- Published
- 2016
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31. Exotic colored scalars at the LHC
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Blum, Kfir, Efrati, Aielet, Frugiuele, Claudia, and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
We study the phenomenology of exotic color-triplet scalar particles $X$ with charge $|Q|=2/3, 4/3,5/3,7/3,8/3$ and $10/3$. If $X$ is a non-singlet of $SU(2)_W$ representation, mass splitting within the multiplet allows for cascade decays of the members into the lightest state. We study examples where the lightest state, in turn, decays into a three-body $W^\pm jj$ final state, and show that in such case the entire multiplet is compatible with existing direct collider searches and indirect precision tests down to $m_X\sim250$~GeV. However, bound states $S$, made of $XX^\dag$ pairs at $m_S\approx2m_X$, form under rather generic conditions and their decay to diphoton can be the first discovery channel of the model. Furthermore, for $SU(2)_W$-non-singlets, the mode $S\to W^+W^-$ may be observable and the width of $S\to\gamma\gamma$ and $S\to jj$ may appear large as a consequence of mass splittings within the $X$-multiplet. As an example we study in detail the case of an $SU(2)_W$ quartet, finding that $m_X\simeq450$~GeV is allowed by all current searches., Comment: 20 pages, 3 figures
- Published
- 2016
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32. The phenomenology of the di-photon excess and $h\to\tau\mu$ within 2HDM
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Efrati, Aielet, Kamenik, Jernej F., and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
The diphoton excess around $m_S=750$ GeV observed at ATLAS and CMS can be interpreted as coming from $S=H$ and $A$, the neutral components of a second Higgs doublet. If so, then the consistency of the light Higgs decays with the Standard Model predictions provides upper bounds on the rates of $S\to VV, hZ, hh$ decays. On the other hand, if $h\to\tau\mu$ decay is established, then a lower bound on the rate of $S\to\tau\mu$ decay arises. Requiring that $\Gamma_S\lesssim45$ GeV gives both an upper and a lower bound on the rotation angle from the Higgs basis $(\Phi_v,\Phi_A)$ to the mass basis $(\Phi_h,\Phi_H)$. The charged scalar, with $m_{H^\pm}\simeq750$ GeV, is produced in association with a top quark, and can decay to $\mu^\pm\nu$, $\tau^\pm\nu$, $tb$ and $W^\pm h$, Comment: 10 pages, 6 figures
- Published
- 2016
33. On a possible large width 750 GeV diphoton resonance at ATLAS and CMS
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Aloni, Daniel, Blum, Kfir, Dery, Avital, Efrati, Aielet, and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
The ATLAS and CMS experiments at the LHC have reported an excess of diphoton events with invariant mass around 750 GeV, with local significance of about $3.6 \sigma$ and $2.6 \sigma$, respectively. We entertain the possibility that this excess is due to new physics, in which case the data suggest a new particle with 13 TeV LHC production cross section times diphoton branching ratio of about 5~fb. Interestingly, ATLAS reports a mild preference for a sizeable width for the signal of about 45 GeV; this result appears consistent with CMS, and is further supported by improving the compatibility of the 8 TeV and 13 TeV analyses. We focus on the possibility that the new state is a scalar. First, we show that, in addition to the new state that is needed directly to produce the diphoton bump, yet more new particles beyond the Standard Model are needed to induce diphoton decay rate of the right size. Second, we note that if the excess is attributed to the Breit-Wigner peak of a single new state, then the signal strength and width -- taken together -- suggest a total LHC production cross section of order $10^5$ fb. Restricting to perturbative models without ad-hoc introduction of many new states or exotic charges, we reach the following conclusions: (i) Gluon-fusion cannot explain the required large production cross section. (ii) Tree level production from initial state quarks cannot explain the required branching ratio to two photons. (iii) Tree level production is constrained by flavor data as well as LHC Run-I and Tevatron dijet analyses. Insisting on a large width we are led to suggest that more than one scalar states, nearly degenerate in mass, could conspire to produce an observed wide bump., Comment: v2: A discussion concerning the flavor constraints in the U(2) symmetry limit added. Contours in Fig. 1 modified. Conclusions left unchanged v3: Journal published version. A discussion concerning the interference in $t\bar t$ searches is added
- Published
- 2015
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34. Lessons from the LHCb measurement of CP violation in Bs→ K+K−
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Nir, Yosef, Savoray, Inbar, and Viernik, Yehonatan
- Published
- 2022
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35. b → cτν¯e,μ contributions to R(D(*))
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Bressler, Shikma, De Vito Halevy, Federico, and Nir, Yosef
- Published
- 2022
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36. Large BR(h->tau mu) in the MSSM?
- Author
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Aloni, Daniel, Nir, Yosef, and Stamou, Emmanuel
- Subjects
High Energy Physics - Phenomenology - Abstract
We study how large the rate of the lepton-flavor violating Higgs decay h->tau mu can be in the (R-parity conserving) MSSM. We make no assumptions, such as universality or alignment, about the flavor structure of the MSSM. We only assume that all couplings and, in particular, the trilinear scalar ones, are perturbative. We take into account lower bounds on the bino and slepton masses from tau->mu gamma and h->gamma gamma as well as upper bounds on the trilinear scalar couplings from the requirement that the global minimum is not charge breaking. We find that in highly fine-tuned regions of parameter space, the ratio BR(h->tau mu)/BR(h->tau tau) can be enhanced by about three orders of magnitude above the estimate from naive dimensional analysis, but still about two orders of magnitude below the present bound. Thus, if h->tau mu is experimentally established to be close to present bounds, the MSSM will be excluded., Comment: 22 pages, 6 figures, version published in JHEP
- Published
- 2015
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37. Probabilistic harmonization and annotation of single‐cell transcriptomics data with deep generative models
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Chenling Xu, Romain Lopez, Edouard Mehlman, Jeffrey Regier, Michael I Jordan, and Nir Yosef
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scRNA‐seq ,harmonization ,annotation ,differential expression ,variational inference ,Biology (General) ,QH301-705.5 ,Medicine (General) ,R5-920 - Abstract
Abstract As the number of single‐cell transcriptomics datasets grows, the natural next step is to integrate the accumulating data to achieve a common ontology of cell types and states. However, it is not straightforward to compare gene expression levels across datasets and to automatically assign cell type labels in a new dataset based on existing annotations. In this manuscript, we demonstrate that our previously developed method, scVI, provides an effective and fully probabilistic approach for joint representation and analysis of scRNA‐seq data, while accounting for uncertainty caused by biological and measurement noise. We also introduce single‐cell ANnotation using Variational Inference (scANVI), a semi‐supervised variant of scVI designed to leverage existing cell state annotations. We demonstrate that scVI and scANVI compare favorably to state‐of‐the‐art methods for data integration and cell state annotation in terms of accuracy, scalability, and adaptability to challenging settings. In contrast to existing methods, scVI and scANVI integrate multiple datasets with a single generative model that can be directly used for downstream tasks, such as differential expression. Both methods are easily accessible through scvi‐tools.
- Published
- 2021
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38. Probing scalar dark matter oscillations with neutrino oscillations
- Author
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Losada, Marta, Nir, Yosef, Perez, Gilad, and Shpilman, Yogev
- Published
- 2022
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39. Model building for flavor changing Higgs couplings
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Dery, Avital, Efrati, Aielet, Nir, Yosef, Soreq, Yotam, and Susič, Vasja
- Subjects
High Energy Physics - Phenomenology - Abstract
If $t\rightarrow hq$ ($q=c,u$) or $h\rightarrow\tau\ell$ ($\ell=\mu,e$) decays are observed, it will be a clear signal of new physics. We investigate whether natural and viable flavor models can saturate the present direct upper bounds without violating the indirect constraints from low energy loop processes. We carry out our analysis in two theoretical frameworks: minimal flavor violation (MFV) and Froggatt-Nielsen symmetry (FN). The simplest models in either framework predict flavor changing couplings that are too small to be directly observed. Yet, in the MFV framework, it is possible to have lepton flavor changing Higgs couplings close to the bound if spurions related to heavy singlet neutrinos play a role. In the FN framework, it is possible to have large flavor changing couplings in both the up and the charged lepton sectors if supersymmetry plays a role.
- Published
- 2014
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40. What if $\lambda_{hhh}\neq 3m_h^2/v$
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Efrati, Aielet and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
A measurement of the Higgs trilinear self coupling $\lambda_{hhh}$ will test the Standard Model Higgs potential. But can it reveal information that cannot be learned otherwise? By analyzing several simple extensions of the Standard Model scalar sector we show that this measurement might give a first hint for New Physics modifying the electroweak symmetry breaking. Combining the measurements of $\lambda_{hhh}$ and $\lambda_{hVV}$ ($V=W,Z$) is particularly powerful in distinguishing between various models of New Physics and in providing unique information on these models., Comment: 17 pages, 2 figures; v2: A few typos corrected and references added
- Published
- 2014
41. Subtleties in the BaBar measurement of time-reversal violation
- Author
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Applebaum, Elaad, Efrati, Aielet, Grossman, Yuval, Nir, Yosef, and Soreq, Yotam
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
A first measurement of time-reversal (T) asymmetries that are not also CP asymmetries has been recently achieved by the BaBar collaboration. We analyze the measured asymmetries in the presence of direct CP violation, CPT violation, wrong strangeness decays and wrong sign semileptonic decays. We note that the commonly used S_{\psi K} and C_{\psi K} parameters are CP-odd, but have a T-odd CPT-even part and a T-even CPT-odd part. We introduce parameters that have well-defined transformation properties under CP, T and CPT. We identify contributions to the measured asymmetries that are T conserving. We explain why, in order that the measured asymmetries would be purely odd under time-reversal, there is no need to assume the absence of direct CP violation. Instead, one needs to assume (i) the absence of CPT violation in strangeness changing decays, and (ii) the absence of wrong sign decays., Comment: 19 pages; v2: Corrections to Eqs. (26,36,37,39,46,47,C2), with corresponding modifications in the text, including the abstract. A new Appendix E
- Published
- 2013
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42. Inference of single-cell phylogenies from lineage tracing data using Cassiopeia
- Author
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Matthew G Jones, Alex Khodaverdian, Jeffrey J Quinn, Michelle M Chan, Jeffrey A Hussmann, Robert Wang, Chenling Xu, Jonathan S Weissman, and Nir Yosef
- Subjects
scRNA-seq ,Single cell ,Lineage tracing ,CRISPR ,Biology (General) ,QH301-705.5 ,Genetics ,QH426-470 - Abstract
Abstract The pairing of CRISPR/Cas9-based gene editing with massively parallel single-cell readouts now enables large-scale lineage tracing. However, the rapid growth in complexity of data from these assays has outpaced our ability to accurately infer phylogenetic relationships. First, we introduce Cassiopeia—a suite of scalable maximum parsimony approaches for tree reconstruction. Second, we provide a simulation framework for evaluating algorithms and exploring lineage tracer design principles. Finally, we generate the most complex experimental lineage tracing dataset to date, 34,557 human cells continuously traced over 15 generations, and use it for benchmarking phylogenetic inference approaches. We show that Cassiopeia outperforms traditional methods by several metrics and under a wide variety of parameter regimes, and provide insight into the principles for the design of improved Cas9-enabled recorders. Together, these should broadly enable large-scale mammalian lineage tracing efforts. Cassiopeia and its benchmarking resources are publicly available at www.github.com/YosefLab/Cassiopeia .
- Published
- 2020
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43. Integrated single cell analysis of blood and cerebrospinal fluid leukocytes in multiple sclerosis
- Author
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David Schafflick, Chenling A. Xu, Maike Hartlehnert, Michael Cole, Andreas Schulte-Mecklenbeck, Tobias Lautwein, Jolien Wolbert, Michael Heming, Sven G. Meuth, Tanja Kuhlmann, Catharina C. Gross, Heinz Wiendl, Nir Yosef, and Gerd Meyer zu Horste
- Subjects
Science - Abstract
Here the authors provide a single-cell characterization of cerebrospinal fluid and blood of newly diagnosed multiple sclerosis (MS) patients, revealing altered composition of lymphocyte and monocyte subsets, validated by other methods including the interrogation of the TFH subset in mouse models of MS.
- Published
- 2020
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- View/download PDF
44. Decision-Making with Auto-Encoding Variational Bayes.
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Romain Lopez, Pierre Boyeau, Nir Yosef, Michael I. Jordan, and Jeffrey Regier
- Published
- 2020
45. Identifying Systematic Variation at the Single-Cell Level by Leveraging Low-Resolution Population-Level Data.
- Author
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Elior Rahmani, Michael I. Jordan, and Nir Yosef
- Published
- 2022
- Full Text
- View/download PDF
46. Higgs couplings to fermions: 2HDM with MFV
- Author
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Dery, Avital, Efrati, Aielet, Hiller, Gudrun, Hochberg, Yonit, and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
We clarify several subtleties concerning the implementation of minimal flavor violation (MFV) in two Higgs doublet models. We derive all the exact and approximate predictions of MFV for the neutral scalar (h,H,A) Yukawa couplings to fermions. We point out several possible tests of this framework at the LHC., Comment: 13 pages
- Published
- 2013
- Full Text
- View/download PDF
47. What if BR(h-->\mu\mu)/BR(h-->\tau\tau) does not equal m_\mu^2/m_\tau^2?
- Author
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Dery, Avital, Efrati, Aielet, Hochberg, Yonit, and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
Measurements of the Yukawa couplings of the recently discovered boson h to fermion pairs will provide a new arena for studying flavor physics. We analyze the lessons that can be learned by measuring the h decay rates into the charged lepton pairs, \tau\tau, \mu\mu, and \tau\mu. We demonstrate how this set of measurements can distinguish in principle between various classes of flavor models such as natural flavor conservation, minimal flavor violation, and Froggatt-Nielsen symmetry., Comment: 14 pages. v2: Minor corrections to Table 1 and Section 7; matches published version
- Published
- 2013
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48. Information Constraints on Auto-Encoding Variational Bayes.
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Romain Lopez, Jeffrey Regier, Michael I. Jordan, and Nir Yosef
- Published
- 2018
49. Implications of Higgs Searches on the Four Generation Standard Model
- Author
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Kuflik, Eric, Nir, Yosef, and Volansky, Tomer
- Subjects
High Energy Physics - Phenomenology - Abstract
Within the four generation Standard Model, the Higgs couplings to gluons and to photons deviate in a significant way from the predictions of the three generation Standard Model. As a consequence, large departures in several Higgs production and decay channels are expected. Recent Higgs search results, presented by ATLAS, CMS and CDF, hint on the existence of a Higgs boson with a mass around 125 GeV. Using these results and assuming such a Higgs boson, we derive exclusion limits on the four generation Standard Model. For m_H = 125 GeV, the model is excluded at 99.9% confidence level. For 124 GeV <= m_H <= 127 GeV, an exclusion limit above 95% confidence level is found., Comment: 4 pages, 2 figures; v2: updated LHC results, refined scan
- Published
- 2012
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- View/download PDF
50. Supersymmetric \Delta A_{CP}
- Author
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Hiller, Gudrun, Hochberg, Yonit, and Nir, Yosef
- Subjects
High Energy Physics - Phenomenology - Abstract
There is experimental evidence for a direct CP asymmetry in singly Cabibbo suppressed D decays, \Delta A_{CP} \sim 0.006. Naive expectations are that the Standard Model contribution to \Delta A_{CP} is an order of magnitude smaller. We explore the possibility that a major part of the symmetry comes from supersymmetric contributions. The leading candidates are models where the flavor structure of the trilinear scalar couplings is related to the structure of the Yukawa couplings via approximate flavor symmetries, particularly U(1), [U(1)]^2 and U(2). The recent hints for a lightest neutral Higgs boson with mass around 125 GeV support the requisite order one trilinear terms. The typical value of the supersymmetric contribution to the asymmetry is \Delta A_{CP}^{SUSY}\sim 0.001, but it could be accidentally enhanced by order one coefficients., Comment: 6 pages. v2: References added
- Published
- 2012
- Full Text
- View/download PDF
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