Sizable NSI from the SU(2)L scalar doublet-singlet mixing and the implications in DUNE

Journal of High Energy Physics, Mar 2017

We propose a novel and simple mechanism where sizable effects of non-standard interactions (NSI) in neutrino propagation are induced from the mixing between an electrophilic second Higgs doublet and a charged singlet. The mixing arises from a dimensionful coupling of the scalar doublet and singlet to the standard model Higgs boson. In light of the small mass, the light mass eigenstate from the doublet-singlet mixing can generate much larger NSI than those induced by the heavy eigenstate. We show that a sizable NSI ε eτ (∼0.3) can be attained without being excluded by a variety of experimental constraints. Furthermore, we demonstrate that NSI can mimic effects of the Dirac CP phase in the neutrino mixing matrix but they can potentially be disentangled by future long-baseline neutrino experiments, such as the Deep Underground Neutrino Experiment (DUNE).

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2FJHEP03%282017%29018.pdf

Sizable NSI from the SU(2)L scalar doublet-singlet mixing and the implications in DUNE

Received: September the SU(2)L scalar doublet-singlet David V. Forero 0 1 2 4 5 Wei-Chih Huang 0 1 2 3 5 Open Access 0 1 2 5 c The Authors. 0 1 2 5 0 We show that a sizable 1 Dortmund , 44221 Germany 2 Blacksburg, VA , 24061 U.S.A 3 Fakultat fur Physik, Technische Universitat Dortmund 4 Center for Neutrino Physics , Virginia Tech 5 [33] DELPHI , ALEPH, SLD, OPAL, L3 collaborations, SLD Electroweak Group, SLD We propose a novel and simple mechanism where sizable e ects of non-standard interactions (NSI) in neutrino propagation are induced from the mixing between an electrophilic second Higgs doublet and a charged singlet. The mixing arises from a dimensionful coupling of the scalar doublet and singlet to the standard model Higgs boson. In light of the small mass, the light mass eigenstate from the doublet-singlet mixing can generate much larger NSI than those induced by the heavy eigenstate. Beyond Standard Model; CP violation; Neutrino Physics - mixing and the implications in 0:3) can be attained without being excluded by a variety of experimental constraints. Furthermore, we demonstrate that NSI can mimic e ects of the Dirac CP phase in the neutrino mixing matrix but they can potentially be disentangled by future long-baseline neutrino experiments, such as the Deep Underground Neutrino Experiment (DUNE). 1 Introduction and general motivations Model NSI Constraints NSI oscillations at DUNE Introduction and general motivations Neutrino oscillations (in the three neutrino framework) are the leading mechanism that explain neutrino avor transitions observed from neutrinos produced in the sun, the Earth atmosphere, reactors, and accelerators. The parameters accounting for neutrino oscillations, the three mixing angles and the two mass squared di erences, have been currently measured within a precision of 8% according to a global t analysis [1]. One additional parameter, which encodes the violation of the charged parity (CP) symmetry in the lepton sector, is still to be determined. This parameter together with the determination of the neutrino mass ordering (normal or inverted hierarchy) are the two main unknowns in the three neutrino framework. Current and future facilities are aimed to nd the two missing pieces and to improve the precision of the oscillation parameters. Better understanding of uncertainties on both theory and experiment sides is crucial in the completion and improvement of our knowledge of the three active neutrino framework. The reactor mixing angle has been measured within a precision of 5% by 1 km baseline reactor neutrino multidetector experiments [2, 3]. The measurement of the atmospheric parameters (the mixing angle and the mass squared di erence) have also been improved in precision thanks to the observations in the disappearance channel by beam-based neutrinos experiments, but still the atmospheric mixing angle is less well-determined among the three mixing angles. However, thanks to the tension in the determination of the reactor mixing angle by current reactor and accelerator experiments, an indication of preferred values for the Dirac CP violating phase have started to emerge [4, 5]. This has opened the possibility of observing CP violation in the lepton sector, which might have an impact in the early Universe. Despite all success so far, upgrades of current and new facilities are needed to probe most of the Dirac CP parameter space, to determine the neutrino mass hierarchy and to improve the precision of the other parameters. In addition to the standard three neutrino oscillation framework, there are wellmotivated scenarios beyond the standard model (SM) that can have phenomenological consequences in neutrino oscillations. This opens the possibility to test new physics along with the standard programs pursued in neutrino oscillation facilities. It would be, for instance, interesting to investigate non-standard neutrino interactions (NSI), non-unitarity neutrino mixing, sterile neutrinos, violation of symmetries, etc. NSI were originally proposed even before neutrino oscillations were proved [6{9] and still today their phenomenological consequences are being studied. NSI can be a byproduct of neutrino mass models and in general are described by e ective four-fermion interaction operators where the strength is characterized by dimensionless couplings (carrying all the avor information) times the Fermi constant. NSI can be of the charged-current (CC) type or of the neutral-current type (NC) depending on the elds involved, and both of types have distinctive phenomenological consequences. The NSI yield additional contributions to the SM weak interactions and therefore constraints can be derived, for instance, from lepton universality and CKM unitarity [10]. In cases where new physics enter above the electroweak scale, both the charged and the neutral sectors are connected (due to the SU(2)L symmetry) and thus stringent constraints from charged lepton avor violating (CLFV) processes can have an impact on the neutral sector [11]. The highlight of this work is to provide a simple mechanism to obtain large NSI e ects and simultaneously avoid these constraints such that one can determine the NSI strength via neutrino oscillation experiments. There exist many particular examples in the literature. In general, the CC-like NSI a ects neutrino production and detection and can be cleanly probed in experiments where neutrino-matter interactions can be neglected, as in reactor neutrino experiments [12] (see also ref. [13]).1 The NC-like NSI a ects the neutrino propagation and can be probed in long-baseline neutrino oscillation experiments since the sensitivity is driven by the neutrino-mater interactions. The current NSI constraints, considering neutrino oscillations only, can be found in ref. [14]. For a general review of the NC-like NSI constraints and phenomenological implications, we refer the reader to ref. [15] and references therein. Among future experiments, the Deep Underground Neutrino Experiment (DUNE) is the main project that will determine the neutrino mass ordering and probe most parameter space of the Dirac CP violating phase. DUNE will use a powerful beam to produce a large number of neutrinos in a broad energy range (roughly between 0.5 and 20 GeV) that will be detected in a 40 t far detector located at 1300 km from the source [16]. As a result, DUNE will be an interesting NSI laboratory. This has been the subject of di erent studies showing that DUNE will be sensitive to the NC-like NSI with couplings of the order of 0:1GF (see for instance [17{19]). More importantly, degeneracies between the NSI couplings and the standard oscillation parameters might challenge the precise determination of the unknown neutrino parameters. This is the case for the determination of the Dirac CP violating phase; the NSI new phases are a new source of the CP violation and one might observe CP violation e ects, which result exclusively from NSI. In a minimal setup, it has been shown that `confusion' can arise with an NSI parameter ("e 0:3) in T2K and NOvA [20, 21] 1Both CC and NC NSI can be tested at the same time in a long-baseline experiment, however, the large number of parameters will decrease the sensitivity for some NSI couplings. (see also ref. [22] in which the `confusion' from "e was examined, after the measurement of 13, at the probability level).2 From the model building point of view, however, it is very challenging to come up with viable models which can produce such `large' NSI couplings and avoid the constraints from CLFV processes. As a result, the main goal of this work is to introduce a mechanism that generates relative large NSI couplings ( 0:3) such that the aforementioned confusion can be realized. Future long-baseline neutrino oscillation experiments such as DUNE, can potentially resolve the confusion and investigate the phenomenological implications of We propose a novel and simple mechanism to obtain large NSI "e . In addition to the SM, there exist an extra SU(2) scalar doublet and a charged SU(2) scalar singlet . The pertinent scalar potential, including the SM Higgs doublet H, is The mixing between and the charged component of arises due to the coupling to the SM Higgs boson, is a dimensionful coupling and hHi = v. In the limit mixing is determined by the ratio of v to 2 while the mass of the light eigenstate m1 is determined by and the v= . These two components can cancel each other such that m1 can be treated as an independent parameter from the mixing angle. The independence is pivotal to achieve large NSI, satisfying various bounds from charged lepton measurements. Yukawa couplings of to leptons are introduced, obeying an imposed Z2 symmetry, under which , and the right-handed electron eR are odd. NSI can be generated through charged currents mediated by the charged component , which is a superposition of the two mass eigenstates in light of the mixing. The light mass eigenstate contribution to NSI can have a large enhancement due to its small mass even if it is suppressed by the mixing angle, in that the mass m1 is independent of the mixing. In other words, the mixing e ect induces an additional contribution from the light eigenstate which can be much larger than the heavy state contribution. Furthermore, large NSI realized via cancellation require ne-tuning and as demonstrated below, taking into account various constraints, the level ne-tuning is needed for have sizable "e ( NSI mediated by alone are classi ed as dimension-6 (d 6) operators in ref. [24] which usually comes with hazardous contributions to CLFV processes, while the mixing-induced NSI belong to d 8 operators (in light of extra hHi2 compared to the d 6 one) and is usually suppressed with respective to d 6 ones. As pointed out in refs. [25, 26], some of d operators only induce lepton avor violation on the neutral sector but not on the charged lepton counterpart such that stringent constraints on charged lepton avor violation can be escaped. In our model, for instance, ! 3e can be engendered by but not mediated by (responsible for NSI). Consequently, sizable NSI do not imply large CLFV e ects. Furthermore, by virtue of the cancellation within m1, the mixing-induced 2For an analytic study of the CP determination in the presence of NSI at low energies, see ref. [23]. On the other hand, with the charged singlet , the neutrino mass can be produced by adding an interaction LcL +, as proposed by Zee [27, 28]. The interaction itself can also yield NSI but it has been shown [29] that considerable NSI will demand large couplings of LcL +, rendering neutrinos too heavy. In contrast, our mechanism is based on cancellation to enhance NSI "e without involving the lepton number violating term LcL + actually forbidden by the imposed Z2 symmetry. Finally, models with a light gauge boson Z0 [30{32] have been proposed to generate considerable NSI but due to various bounds, "e is constrained to be much less than 0:3. The paper is organized in the following. In section 2, we specify the model setup, followed by discussion of how sizable NSI can be attained via the doublet-singlet mixing in section 3. Various constraints are taken into account in section 4. Then we perform the numerical analysis in the context of long-baseline neutrino experiments in section 5. Finally, we conclude in section 6. We enlarge the SM particle content by including two scalar elds, one SU(2)L doublet and one charged singlet . Furthermore, we impose a Z2 symmetry under which , the right-handed electron are odd while the rest of SM particles are even: where the entries in the parentheses denote the SM SU(3)c U(1)Y quantum numbers as well as the Z2 parity. The reason of including the Z2 symmetry is to avoid a myriad of experimental constraints from the charged lepton sector. Note that the Z2 symmetry is broken by the SM electron Yukawa coupling and it is arguable that the smallness of the coupling results from the Z2 symmetry protection. The relevant terms in the scalar potential read, where H is the SM Higgs doublet, is a dimensionful coupling and we focus on regions of the parameter space where do not develop the vacuum expectation value (VEV). On the other hand, the mixing between arises due to the SM Higgs VEV v, and the mass matrix of In the limit of , the masses of the two eigenstates s1 and s2 are M 2 = is the avor index, representing e and but not in that we concentrate on e ects of "e , relevant for the confusion mentioned above. mixing, the e ective operator of the charged current, after integrating out heavy , reads ) = where the second equality comes from Fierz transformation. Comparing with the charged current mediated by the W boson, v= 2. Note that because of cancellation between can be treated as an independent parameter from the mixing angle although, without any ne-tuning, it is expected that m21 v = 2 and m1=m2. Finally, we would like to point out that the neutrino mass can be generated by adding Lc Lc (Zee model [27, 28]), which however breaks the Z2 symmetry, or simply by including heavy right-handed neutrinos (Type-I seesaw). The correlation between the neutrino mass mechanism and NSI, however, will not be explored here. To realize NSI, we couple the SU(2)L doublet to SM leptons via a renormalizable operator. In light of Z2 under which , and the right-handed electron eR are odd, the only allowed Now, we can estimate the magnitude of the NSI from s1 and s2. The s2-induced contribution, assuming e one can obtain After taking into account the mixing, the NSI from the two mass eigenstates s1 and "s1 = "s2 = "s2 = while the s1 contribution can be rewritten as "s1 = m1=m2 As we shall see below, due to the constraint on the CLFV process ! 3e, is restricted to be smaller than 0.16 for TeV s2. It implies the s2-induced NSI contribution can not be considerable. Nevertheless, the s1 contribution can be large since m1 and can be regarded v = 2 It implies that in order to obtain a sizable NSI contribution of order O(0:1), the ne-tuning on the cancellation between 2 and 2 2 v = 2 is required to be around the level of 0:1%. Due to the existence of the couplings of to the SM leptons, we here consider constraints involving charged leptons e and from various measurements. LEP constraints on the mass of s1. From the LEP measurements on the Z decay width, the non-SM contribution are bounded below 2:9 MeV [33], which requires that m1 should be larger than half of the Z mass to kinetically forbid Z decay into s1 s1 . Besides, the LEP charged Higgs (H ) searches [34] based on e+e ! Z ! H+H , followed by H a limit of mH > 80 GeV in the context of two Higgs doublet models. It also applies to s1 in our model. Therefore, we have m1 & 80 GeV. The LEP measurements on the cross-section of e+e can be translated into constraints on the new physics scale in the context of e ective four-fermion Le = structive) interference between the SM and new physics processes. In our model, e+e processes will be mediated by solely 0 of mass m (' m2), which can be described by e ective operators Le = j2mej22 (eL = 9:1 TeV for e+e = 10:2 TeV for e+e infer e=m2 . 0:39=TeV and =m2 . 0:49=TeV. Finally, the last LEP constraint comes from DM searches based on the mono-photon the internal bremsstrahlung. In our model, we have similar mono-photon events comes from the initial state radiation or via the s1-exchange. The constraint on DM searches can be LEP mono-photon constraints. signal [36]: e+e i.e., (1=2 1=2)2, and (left-handed e+) and left-handed ) are involved, DM ' 320 GeV for very small DM masses [36]. In the limit of e , the constraint is reduced to and from eq. (3.5), it implies the maximum NSI is j"s1 j = which is consistent with results in refs. [25, 37] based on e+e the context of NSI. Note that the mono-photon bound on NSI is unavoidable in the model since it is the same interactions that contribute to both NSI and the mono The bound derived above is actually more stringent than needed since all the relevant processes in question are t-channel ones, and so one has, for the propagator, j1=((pe m21)j ' j1=(2pe p m21)j . 1=m21, where pe ( ) is the four momentum of the initial electron ( nal neutrino). The contribution to mono-photons from s2 NSI as explained in eq. (3.8). 0 will induce which can be rewritten as we will not consider bounds from the e at tree level since only couples to eR but not R. Therefore, branching ratio measurements. decay3 and the decay width normalized to the W is constrained by null ! 3e results from Belle collabora!3e = = 0:3 and m2 = 10 TeV. The purple, red and crosshatched areas are excluded by the LEP charged Higgs searches, range from 80 to 105 GeV. and is stronger than the LEP constraints on e+e similarly impose the bound from the fact Br( ! 3e measurements if implies that in order to achieve a sizable e , the ne-tuning between 2 and 2 2 v = 2 mentioned in eq. (3.8) has to be at the level of 10 5. As mentioned above, sizable NSI induced via the mixing fall into the category of d 8 operators for which there is not always direct correlation between is switched on. Due to =m2 . 8:12 10 3=TeV. It ! e+e e does not receives the same enhancement NSI and CLFV interactions: from the s1-exchange as NSI. 0 will also radiatively induce ! 3e by closing the e+ and e lines with a photon insertion. Therefore, suppressed by two powers of the electric coupling constant as well as a loop factor, which amount to 10 3 or so compared to constrains on these two processes are similar, Br( ! 3e. Given that the experimental 10 8 [39] versus 10 8 [38], we will not include the ! e and the process actually stems from the process The constraints are summarized in gure 1, where we choose = 0:3 and m2 = 10 TeV. The purple area is excluded by the LEP searches on the charged Higgs, the light red area is eliminated by the Belle ! 3e bound which are more stringent than the LEP bounds on ! `+` , while the crosshatched region will be disfavored by the LEP mono-photon searches. To achieve sizable NSI of 0:3, m1 is constrained to be between 80 and 105 GeV. Finally, we comment on the constraint from the electron magnetic dipole moment and implications on the IceCube experiment. At one-loop level, the electron anomalous magnetic moment (g 2) receives an additional radiative contribution from loops of and e. The contribution can be estimated as: for the region of interest in gure 1. It is much smaller than the di erence between the experiment result and the SM prediction: aeexp Therefore, the new contribution to ae is negligible. 10 12 [40{43]. As pointed out in ref. [44], the resonance enhancement with a single scalar leptoquark can be used to increase the very high energy shower event rates at the IceCube. In our model, high energy neutrinos can interact with electrons and produce or , which later decays into neutrinos and charged leptons. To have on-shell, one must have & m ; , requiring E 10 and 105 PeV for m 100 GeV and m ux of such high energy cosmic neutrinos is then highly suppressed. Moreover, the relevant coupling for the -exchange has to be of O(1) [44] so that the new contribution is comparable with that of the SM. Nonetheless, the coupling in this model is simply that is much smaller than the unity for regions of interest. As a result, one can not account for PeV events at the IceCube with the resonance enhancement of NSI oscillations at DUNE A NC-like NSI interaction can be parametrized as four-fermion e ective operators of LNNSCI = where GF is the Fermi constant, "f;P are the NSI dimensionless couplings whose absolute SM fermion of the rst family: e, u, and d. The NSI e ective interactions modify the e ective matter potential that accounts for the neutrino-mater interactions. Therefore, there is a dependency on the fermion density in the medium. For long baselines below 2000 km, one can assume the matter density is constant simplifying the expression for the Hamiltonian in presence of the NSI, which can be written as: with V = p Hint = V B 2 GF Ne, where Ne is the electron density on Earth. Notice that the `1' in the interaction Hamiltonian corresponds to the SM neutrino-matter interactions. By adding the NSI coupling in the formalism, we have increased the number of real parameters by eight since, in the diagonalization, one of the diagonal parameters can be rephased out. It is worth to mention that long baseline neutrino oscillations are sensitive to a combination of NSI couplings de ned in eq. (5.1): = "e where Y is the abundance of each fermion in the medium. In eq. (5.3) the e ective NSI couplings are a weighted combination of the Lagrangian parameters. The vacuum neutrino oscillations are governed by the usual Hamiltonian H0 = where U is the lepton mixing matrix, m2k1 are the two measured mass squared di erences, and E is the energy of the incoming neutrino. The total Hamiltonian describing neutrino oscillations in matter is the sum of eq. (5.2) and eq. (5.4). since the imposed Z2 symmetry forbids Yukawa couplings of to quarks. To simplify the analysis, we set e = eq. (3.4), we have the following relations: is the Yukawa coupling of de ned in eq. (3.1). From "ee = " "e = j"j exp (i ); which are similar to those of a recent work [45], that features a light gauge boson Z0 corresponding to the U(1)B or U(1)B L gauge symmetry and can also generate large NSI, including "e . For the numerical analysis we have used the GLoBES library [46, 47] and the NSI tool (prepared for the study in ref. [48]) with the o cial implementation of the DUNE experiment from ref. [49]. In the analysis we have included the full DUNE implementation, i.e. the four oscillation channels for (anti-)neutrino appearance and disappearance running 3:5 years in each mode with the optimized neutrino beam. Also, we included the e ect of the systematical errors in our analysis. Finally, as `true' parameters, we used the best- t values for the standard oscillation parameters from ref. [1] except for the reactor mixing angle, whose value was xed to the Daya Bay result from ref. [2]. The atmospheric mixing angle is assumed maximal but large errors on the atmospheric parameters (with the current precision) were implemented as penalties in the 2 statistical analysis. Our analysis is based on the normal neutrino mass hierarchy (NH) and we commented on the relevant di erences in the case of the inverted mass hierarchy (IH) at the end. Initially, we have extracted a constraint on the NSI couplings in our simpli ed setup by assuming only standard oscillation parameters as the `true' parameters and by testing the NSI couplings. The results are shown in the left panel of gure 2 where the dependency on the `true' Dirac CP phase value is also shown. All the parameters not shown in the plot have been marginalized over except for the solar oscillation parameters and the reactor mixing angle that were xed to their best- t values.5 We have obtained the allowed interval 4Since one of the diagonal NSI parameters is irrelevant in the diagonalization of the Hamiltonian in eq. (5.2), one can set " equal to zero which implies = 0. However, terms in addition to diagonal one. The resulting o -diagonal terms in principle a ect the oscillation NSI analysis although the e ect is small. Therefore, in our analysis we have assumed = 0 without signi cantly a ecting the CP degeneracy mentioned above. 5The central values and uncertainties for the oscillation parameters ( ij, m2k1), that are marginalized over, are obtained from the global t analysis [1] assuming standard interactions only, i.e., in the absence = 0 also induces two o -diagonal in eq. (5.5). Most of the parameters not shown in the plot were marginalized over. See text for details. In the right panel, we show the bi-rate plots that identi es the parameter degeneracies. The solid line corresponds to the case with SM interactions and for all Dirac CP phase values. The dashed and dotted curves correspond to the NSI case, for all possible NSI phase values, and for =2 denoted by the cross is also shown including the statistical uncertainty as a reference. In this case, the standard oscillation parameters not shown were xed to their best- t values. " 2 [ 0:16; 0] at the 90% con dence level for 1 d.o.f.. This limit can not be directly compared with with existing works in refs. [18, 19] due to the correlations in eq. (5.5) from our model. Notice that, in our model, only the "e couplings are predicted and therefore NSI constraints from neutrino-electron scattering also apply. However, the bound extracted from DUNE simulated data is compatible with the scattering NSI bounds in refs. [50{52] by identifying "e = "eR + "eL. CP = CP = CP = In order to evidence the parameter degeneracies after the inclusion of the NSI couplings, we have made use of the total signal rates shown in the a bi-rate plot in the right panel of gure 2. In the same spirit of ref. [20], the `true' Dirac CP phase values were assumed to be CP conserving to explore the possibility that the new phase, coming from the NSI, could mimic the e ect of the standard Dirac CP phase | what we call the `confusion'. For including the statistical errors. This point is one of the probable values within the allowed range of the Dirac CP phase determined by the T2K and NOvA [4, 5] measurements after including the reactor mixing angle determined at reactors. In the case the value since the maximum neutrino rates are comparable with the SM prediction with and SM ellipses, there is an ample room for the confusion to happen. In other words, CP phase are shown for both the SM and NSI cases. We have xed the NSI magnitude to the value j"j = 0:1 (see also eq. (5.5)) and for the di erent NSI phases panel the minimum 2 distributions are shown for the SM and NSI cases showed in the left panel. showed in the plot. In the right All not shown parameters were marginalized over, see text for details of the analysis. considering that the current preferred values span the complete negative region of the within the interval [ 1; 0]. We now are in a position to quantify the degree of `confusion' in the establishment of CP violation in the lepton sector in DUNE. The magnitude of the NSI couplings regarded Statistical uctuations in the `true' rates are included and we test the standard oscillation rates. In the left panel of gure 3, we show the distribution of the best- t value of CP for di erent values of the new phase . For comparison, we also display the case without NSI, which appears distributed around CTrPue = as expected. Given the chosen values of the ( = , 11 =12, 5 =6, ; =2]. Except for the case of the reference value ` at the 90% con dence level for the normal hierarchy [53]. Thus, if DUNE measures a value of the CP violating phase close to 3 =4 (away from the current best- t value), the degeneracy will persist. Otherwise, DUNE might break the degeneracy, strongly depending on its precision on the CP violating phase measurement. 2 distributions for each of standard and NSI cases in the left panel of gure 3 are shown in the right panel of the same gure. Except for the case of the histograms of the NSI and the standard cases are centered around is compatible with the number of bins minus that of the tted parameters, and is within a deviation of less than ten 2min units. This evidences the possibility that DUNE might not have the ability to distinguish the origin of the CP violation if the measured CP phase happens to be around 3 =4. Finally, in the case of the IH, the constraint on j"j is similar to that of the NH case, shown in the left panel of gure 2 and it is even stronger for certain values of CtrPue. The parameter degeneracy shown in the right panel of gure 2 for NH is also present in the CP = 0. This is due to the fact that for IH in DUNE, with CP = =2, lower neutrino rates and centered around CP = with the current preferred one CP break the degeneracy. Notice that we here have xed =2 [53] and therefore it is likely that DUNE will CP True = 0 but one can have mixed sources of CP violation from both the SM and NSI. In contrast, in the NH case even for a DUNE, as demonstrated in gure 3. We come up with a novel way to achieve sizable NSI of order O(0:3) at the cost of netuning, which is required to be at the level of 10 3 . In addition to the SM particles, the extra SU(2) doublet and charged singlet scalars, denoted by introduced as well as the Z2 symmetry, under which , and the right-handed electron eR are odd. The charged component of via the dimensionful coupling electron Yukawa coupling and it is plausible that the smallness of the coupling is protected by the Z2 symmetry. If there exists the mass hierarchy, m2 m2 , the mass of the light mass eigenstate s1 can be treated as an uncorrelated parameter from the mixing angle at the price of ne-tuning. As a result, one can have a very small mass of s1, m1, but a relatively large mixing angle . Note that without ne-tuning one has m1=m2, where m2 is the mass of the heavy eigenstate s2. An analogy can be drawn between this model and hybrid models of the Type-I plus Type-II seesaw mechanism, where light neutrino masses similarly receive two contributions from the mixing with heavy right-handed neutrinos and from the VEV of the SU(2)L triplet scalar. The light-heavy neutrino mixing angle is merely determined by the heavy neutrino mass and the Yukawa coupling but is not related to the triplet VEV. NSI can be generated by coupling to eR and the SU(2)L lepton doublets L ( = e; ), eR which obeys the Z2 symmetry. The new Yukawa coupling will give rise to NSI via the is not considered here since it has a little impact on the `confusion' we look for. In light of the mixing, NSI from s1 is can be sizable if 2=m21 2=m21, which as the LEP measurements on the e+e ! `+` cross-section, upper limits on ! e branching ratios, e; are constrained to less than 0.16 for TeV s2, while the LEP searches on the charged Higgs demand m1 to be greater than 80 GeV. All in all, one needs m21=m22 10 3 2 such that "e can be as large as 0.3 with m1 100 GeV, given and m2 & 10 TeV. The inevitable upper bound on "e comes from the LEP mono-photon searches since in our model both NSI and mono-photon signals result from exactly the same interactions. detection of e+e gun for the 0 existence. The extra particles in the model are within the reach of future experiments. First, the LEP mono-photon search has limited "e to be smaller than 0:3. Future electron colliders such as ILC [54, 55] or FCC-ee (formerly known as TLEP,) [56, 57] can signi cantly improve the mono-photon bound or spot the signal, which is an indirect evident of the charged . Second, the accessible branching fractions for superKEKB/Belle II will reach the level of O(10 10) [58, 59], discovery of will implicitly indicate the presence of the neutral component 0. Third, the direct + at high-luminosity ILC and FCC-ee will be a smoking We have also discussed the phenomenological implications from the induced NSI. One of the main objectives of the future neutrino program is to establish if there is CP violation in the lepton sector with the help of current and future facilities. DUNE is one of the future facilities that will shed light on the current unknowns in the three neutrino framework and in particular on the determination of the CP violating phase. In this work we have which results in the correlations in eq. (5.5). We have extracted the bound " 2 [ 0:16; 0] at the 90% con dence level Since DUNE is sensitive to an NSI at the 10% level, we also studied the NSI impact on the determination of the CP violating phase. To this purpose, we have exploited the parameter degeneracies that arise due to the new parameters coming form the NSI. One of the main consequences is the possible `confusion' in terms of the source of the CP violation. We have study the degree of `confusion' at DUNE experiment by setting the Dirac CP phase to a CP conserving value and allowing the "e NSI phase to generate the observed CP violation. We have found that if DUNE measures a phase close 3 =4 ( 135 ) instead of measured CP violation. Otherwise, if DUNE measures a CP phase di erent from 3 =4 with a precision better than 10 then it will be able to break the standard and NSI CP degeneracy studied here. Finally, we would like to point out that by having couple to quarks, one also get large NSI from quark-neutrino interactions. It is possible to realize the \dark-side" solution for solar neutrinos proposed in refs. [60, 61] as an alternative to the standard LMA solution based on the Mikheev-Smirnov-Wolfenstein mechanism [6, 62]. Bounds on NSI from LHC mono-jet searches [63], however, will come into play in this case. Some models [30, 31, 45] have recently been proposed to realize such large NSI. The authors would like to thank Andre de Gouv^ea and So ane M. Boucenna for helpful discussions, and thank Joachim Brod and Andre de Gouv^ea for useful comments on the draft. WCH is grateful for the hospitality of Northwestern University HEP group where the project was initiated. WCH is supported by DGF Grant No. PA 803/10-1. DVF thanks the URA fellowship that allowed him to visit the theory division at Fermilab where this project was initiated. DVF has been supported by the U.S. Department of Energy under the DE-SC0013632 and DE-SC0009973 contracts. Open Access. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. (2014) 093006 [arXiv:1405.7540] [INSPIRE]. [arXiv:1505.03456] [INSPIRE]. Reactor Antineutrino Disappearance in the RENO Experiment, Phys. Rev. Lett. 116 (2016) 211801 [arXiv:1511.05849] [INSPIRE]. [4] T2K collaboration, K. Abe et al., Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6:6 D 91 (2015) 072010 [arXiv:1502.01550] [INSPIRE]. 1020 protons on target, Phys. Rev. [5] NOvA collaboration, P. Adamson et al., First measurement of electron neutrino appearance in NOvA, Phys. Rev. Lett. 116 (2016) 151806 [arXiv:1601.05022] [INSPIRE]. (1987) 432 [INSPIRE]. R935(R) [INSPIRE]. no mixing in the vacuum, Phys. Lett. B 260 (1991) 154 [INSPIRE]. neutrino interactions, JHEP 08 (2009) 090 [arXiv:0907.0097] [INSPIRE]. avor violating interactions explain the atmospheric neutrino problem?, Phys. Rev. D 61 (2000) 053005 [hep-ph/9909390] Interactions at Daya Bay, JHEP 07 (2015) 060 [arXiv:1412.1064] [INSPIRE]. at medium-baseline reactor antineutrino experiments, Phys. Lett. B 728 (2014) 148 [arXiv:1310.5917] [INSPIRE]. analysis of neutrino oscillation data, JHEP 09 (2013) 152 [arXiv:1307.3092] [INSPIRE]. [15] O.G. Miranda and H. Nunokawa, Non standard neutrino interactions: current status and future prospects, New J. Phys. 17 (2015) 095002 [arXiv:1505.06254] [INSPIRE]. Underground Neutrino Experiment (DUNE), arXiv:1512.06148 [INSPIRE]. [17] M. Masud, A. Chatterjee and P. Mehta, Probing CP-violation signal at DUNE in presence of non-standard neutrino interactions, J. Phys. G 43 (2016) 095005 [arXiv:1510.08261] 908 (2016) 318 [arXiv:1511.05562] [INSPIRE]. [19] P. Coloma, Non-Standard Interactions in propagation at the Deep Underground Neutrino Experiment, JHEP 03 (2016) 016 [arXiv:1511.06357] [INSPIRE]. 117 (2016) 031801 [arXiv:1601.03736] [INSPIRE]. from nonstandard interactions, Phys. Rev. D 93 (2016) 093016 [arXiv:1601.00927] [22] A. Friedland and I.M. Shoemaker, Searching for Novel Neutrino Interactions at NOvA and Beyond in Light of Large 13, arXiv:1207.6642 [INSPIRE]. neutrino oscillations at low energies, JHEP 10 (2016) 138 [arXiv:1607.08513] [INSPIRE]. neutrino interactions, Phys. Rev. D 79 (2009) 013007 [arXiv:0809.3451] [INSPIRE]. [25] Z. Berezhiani and A. Rossi, Limits on the nonstandard interactions of neutrinos from e+e colliders, Phys. Lett. B 535 (2002) 207 [hep-ph/0111137] [INSPIRE]. nonstandard neutrino interactions, JHEP 03 (2003) 011 [hep-ph/0302093] [INSPIRE]. [27] A. Zee, A Theory of Lepton Number Violation, Neutrino Majorana Mass and Oscillation, Phys. Lett. B 93 (1980) 389 [Erratum ibid. B 95 (1980) 461] [INSPIRE]. model, Phys. Lett. B 681 (2009) 269 [arXiv:0909.0455] [INSPIRE]. [30] Y. Farzan, A model for large non-standard interactions of neutrinos leading to the LMA-Dark solution, Phys. Lett. B 748 (2015) 311 [arXiv:1505.06906] [INSPIRE]. [31] Y. Farzan and I.M. Shoemaker, Lepton Flavor Violating Non-Standard Interactions via Light Mediators, JHEP 07 (2016) 033 [arXiv:1512.09147] [INSPIRE]. 030005 [INSPIRE]. Heavy Flavour Group and LEP Electroweak Working Group, S. Schael et al., Precision electroweak measurements on the Z resonance, Phys. Rept. 427 (2006) 257 [hep-ex/0509008] [INSPIRE]. [35] DELPHI, LEP, ALEPH, OPAL, L3 collaborations, SLD Electroweak Group, SLD Heavy Flavor Group and LEP Electroweak Working Group, A Combination of preliminary electroweak measurements and constraints on the standard model, hep-ex/0312023 [INSPIRE]. 84 (2011) 014028 [arXiv:1103.0240] [INSPIRE]. Three Leptons with 719 Million Produced [arXiv:1001.3221] [INSPIRE]. Pairs, Phys. Lett. B 687 (2010) 139 [39] BaBar collaboration, B. Aubert et al., Searches for Lepton Flavor Violation in the Decays [40] D. Hanneke, S. Fogwell and G. Gabrielse, New Measurement of the Electron Magnetic Moment and the Fine Structure Constant, Phys. Rev. Lett. 100 (2008) 120801 [arXiv:0801.1134] [INSPIRE]. [42] T. Aoyama, M. Hayakawa, T. Kinoshita and M. Nio, Tenth-Order QED Contribution to the 2 and an Improved Value of the Fine Structure Constant, Phys. Rev. Lett. 109 (2012) 111807 [arXiv:1205.5368] [INSPIRE]. [44] B. Dutta, Y. Gao, T. Li, C. Rott and L.E. Strigari, Leptoquark implication from the CMS and IceCube experiments, Phys. Rev. D 91 (2015) 125015 [arXiv:1505.00028] [INSPIRE]. [46] P. Huber, M. Lindner and W. Winter, Simulation of long-baseline neutrino oscillation experiments with GLoBES (General Long Baseline Experiment Simulator), Comput. Phys. Commun. 167 (2005) 195 [hep-ph/0407333] [INSPIRE]. of neutrino oscillation experiments with GLoBES 3.0: General Long Baseline Experiment Simulator, Comput. Phys. Commun. 177 (2007) 432 [hep-ph/0701187] [INSPIRE]. CDR, arXiv:1606.09550 [INSPIRE]. E ort and World Wide Study, arXiv:0712.1950 [INSPIRE]. Volume 2: Physics at the ILC, arXiv:0709.1893 [INSPIRE]. [1] D.V. Forero , M.A. Tortola and J.W.F. Valle , Neutrino oscillations re tted , Phys. Rev. D 90 [2] Daya Bay collaboration , F.P. An et al., New Measurement of Antineutrino Oscillation with the Full Detector Con guration at Daya Bay , Phys. Rev. Lett . 115 ( 2015 ) 111802 [3] RENO collaboration , J.H. Choi et al., Observation of Energy and Baseline Dependent [6] L. Wolfenstein , Neutrino Oscillations in Matter, Phys. Rev . D 17 ( 1978 ) 2369 [INSPIRE]. [7] J.W.F. Valle , Resonant Oscillations of Massless Neutrinos in Matter, Phys. Lett . B 199 [8] E. Roulet , MSW e ect with avor changing neutrino interactions , Phys. Rev. D 44 ( 1991 ) [9] M.M. Guzzo , A. Masiero and S.T. Petcov , On the MSW e ect with massless neutrinos and [10] C. Biggio , M. Blennow and E. Fernandez-Martinez , General bounds on non-standard [11] S. Bergmann , Y. Grossman and D.M. Pierce , Can lepton [12] S.K. Agarwalla , P. Bagchi , D.V. Forero and M.A. Tortola , Probing Non-Standard [13] T. Ohlsson , H. Zhang and S. Zhou , Nonstandard interaction e ects on neutrino parameters [20] D.V. Forero and P. Huber , Hints for leptonic CP-violation or New Physics?, Phys. Rev. Lett. [28] A. Zee , Charged Scalar Field and Quantum Number Violations, Phys. Lett. B 161 (1985) 141 [29] T. Ohlsson , T. Schwetz and H. Zhang , Non-standard neutrino interactions in the Zee -Babu [32] P.A.N. Machado , Flavor e ects at the MeV and TeV scales , AIP Conf. Proc . 1743 ( 2016 ) [34] LEP, DELPHI, OPAL, ALEPH and L3 collaborations , G. Abbiendi et al., Search for Charged Higgs bosons: Combined Results Using LEP Data, Eur. Phys. J. C 73 ( 2013 ) 2463 [36] P.J. Fox , R. Harnik , J. Kopp and Y. Tsai , LEP Shines Light on Dark Matter , Phys. Rev . D [37] M.B. Wise and Y. Zhang , E ective Theory and Simple Completions for Neutrino [38] Belle collaboration , K. Hayasaka et al., Search for Lepton Flavor Violating Tau Decays into [41] D. Hanneke , S.F. Hoogerheide and G. Gabrielse , Cavity Control of a Single-Electron Quantum Cyclotron: Measuring the Electron Magnetic Moment , Phys. Rev . A 83 ( 2011 ) [43] M. Endo , K. Hamaguchi and G. Mishima , Constraints on Hidden Photon Models from 2 and Hydrogen Spectroscopy, Phys. Rev. D 86 (2012) 095029 [45] Y. Farzan and J. Heeck , Neutrinophilic nonstandard interactions , Phys. Rev. D 94 ( 2016 ) [47] P. Huber , J. Kopp , M. Lindner , M. Rolinec and W. Winter , New features in the simulation [48] J. Kopp , M. Lindner , T. Ota and J. Sato , Non-standard neutrino interactions in reactor and superbeam experiments , Phys. Rev. D 77 ( 2008 ) 013007 [arXiv:0708.0152] [INSPIRE]. [49] DUNE collaboration, T. Alion et al., Experiment Simulation Con gurations Used in DUNE electrons, Phys. Rev. D 84 ( 2011 ) 013002 [INSPIRE]. [50] D.V. Forero and M.M. Guzzo , Constraining nonstandard neutrino interactions with [51] J. Barranco , O.G. Miranda , C.A. Moura and J.W.F. Valle , Constraining non-standard neutrino-electron interactions , Phys. Rev. D 77 ( 2008 ) 093014 [arXiv:0711.0698] [INSPIRE]. [52] A.N. Khan , Global analysis of the source and detector nonstandard interactions using the e scattering data , Phys. Rev. D 93 (2016) 093019 [53] K. Iwamoto , Recent Results from T2K and Future Prospects, talk given at 38th International Conference on High Energy Physics (ICHEP 2016 ), Chicago, IL, U.S.A., 3 { 10 August 2016 [54] ILC collaboration, A. Puntambekar et al ., ILC Reference Design Report: ILC Global Design [55] ILC collaboration, G. Aarons et al., International Linear Collider Reference Design Report [56] A. Blondel and F. Zimmermann , A High Luminosity e+e Collider in the LHC tunnel to study the Higgs Boson , arXiv:1112.2518 [INSPIRE]. TLEP, JHEP 01 ( 2014 ) 164 [arXiv:1308.6176] [INSPIRE]. [57] TLEP Design Study Working Group , M. Bicer et al., First Look at the Physics Case of [58] Belle-II collaboration, T. Abe et al., Belle II Technical Design Report, arXiv:1011. 0352 [59] Belle and Belle-II collaborations , K. Hayasaka, Results and prospects on lepton avor violation at Belle/Belle II, J. Phys. Conf. Ser . 408 ( 2013 ) 012069 [INSPIRE]. [60] O.G. Miranda , M.A. Tortola and J.W.F. Valle , Are solar neutrino oscillations robust? , JHEP 10 ( 2006 ) 008 [hep-ph/0406280] [INSPIRE]. [61] F.J. Escrihuela , O.G. Miranda , M.A. Tortola and J.W.F. Valle , Constraining nonstandard neutrino-quark interactions with solar, reactor and accelerator data , Phys. Rev. D 80 ( 2009 ) 105009 [Erratum ibid . D 80 ( 2009 ) 129908] [arXiv:0907.2630] [INSPIRE]. [62] S.P. Mikheev and A.Y . Smirnov , Resonance Ampli cation of Oscillations in Matter and Spectroscopy of Solar Neutrinos , Sov. J. Nucl. Phys . 42 ( 1985 ) 913 [Yad . Fiz. 42 ( 1985 ) [63] A. Friedland , M.L. Graesser , I.M. Shoemaker and L. Vecchi, Probing Nonstandard Standard Model Backgrounds with LHC Monojets, Phys. Lett . B 714 ( 2012 ) 267 [arXiv:1111.5331]


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2FJHEP03%282017%29018.pdf

David V. Forero, Wei-Chih Huang. Sizable NSI from the SU(2)L scalar doublet-singlet mixing and the implications in DUNE, Journal of High Energy Physics, 2017, 18, DOI: 10.1007/JHEP03(2017)018